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HILFIELD PARK RESERVOIR WILDLIFE REPORT 2013

Hilfield Park Reservoir Wildlife Report 2013

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HILFIELD PARK RESERVOIR WILDLIFE REPORT FOR 2013

CONTENTS

Introduction 2

List of contributors 2

Review of 2013 Peter Delaloye 3

Birds, systematic list Mark McManus and Eirwen Edwards 4

Birds year-by-year review Bob Cripps 27

Ringing report Mike Beatley 33

Butterflies Steve Murray 42

Dragonflies Steve Murray 47

Mammals, reptiles and amphibians Bob Cripps 50

Moths 2013 Rachel Terry 52

The ultraviolet reflectance of feathers Richard Melzack Ph.D 58

Herts & Middlesex Wildlife Trust 68


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INTRODUCTION

Hilfield Park Reservoir is a Local Nature Reserve in the ownership of Affinity Water (previously Veolia

Water). It was established as a nature reserve in 1969, after an agreement between the company

and Hertfordshire County Council, with management undertaken by Herts & Middlesex Wildlife

Trust (HMWT).

The water surface covers about 46 hectares (115 acres) at top level and is surrounded by 32

hectares (80 acres) of woodland, bramble scrub and grassland with a number of ponds. The

storage capacity of the reservoir is approximately 600 million gallons.

This is the twenty-third report, continuing to encourage a wider interest in the site and the

recording of its wildlife.

I would like to thank everyone who contributed to this report. Special thanks are due to Stephen

Murray, Bob Cripps, Mark McManus, Eirwen Edwards, Rachel Terry, Rob Hopkins, Tony Blake, Jack

Fearnside and Mike Beatley without whom it would not have been possible to prepare this report.

All future records of any aspect of natural history relating to the reserve would be gratefully

received.

I would also like to take this opportunity to request that both authors and the report itself are

acknowledged fully, following part or complete use of this report as reference.

Peter Delaloye

HMWT Volunteer Warden

LIST OF CONTRIBUTORS

We are grateful to the following for submitting records. All records have been submitted to the

county recorder.

J. Bailey

M. Beatley

I. Bennell

T. Blake

R. Boyden

D. Chandler

K. Cramer

R. Cripps

P. Delaloye

E .Edwards

J. Fearnside

E. Inzani

H. Inzani

P. McManus

M. McManus

R. Melzack

J. Moss

M. Murphy

S. Murray

P. Peretti

M. Rossor

E. Stainthorpe

R. Terry

J. Thompson


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REVIEW OF 2013

Pride of place this year goes to the insects.

On 6 October Stephen Murray discovered a Vagrant Emperor dragonfly near the south east bay, not

only the first sighting for Hilfield, but also the first for Hertfordshire. This records has been accepted

by the national dragonfly rarities committee.

Not to be outdone, butterflies provided three new species for the site: Purple Emperor, Silver-

washed Fritillary and Chalkhill Blue.

Meanwhile Rachel Terry’s moth report for 2013 includes nearly 60 new species for the reserve!

It was another poor year for the breeding Black-necked Grebes, but two young did fledge.

Other notable bird records were:

The first Wood Warbler to be ringed at the reservoir (last sighting in 2001)

The second occurrence of Cetti’s Warbler (both ringed, the first in 2003)

A juvenile/first winter Grey Phalarope (the last in 2008).

Once again we would like to thank Rob Hopkins of HMWT and his Green Team who have carried

out vital work around the reserve, particularly cutting back overgrown vegetation on the south

bank.

Peter Delaloye

HMWT Volunteer Warden


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BIRDS OF HILFIELD PARK RESERVOIR 2012

MUTE SWAN Cygnus olor

One pair bred with six cygnets first noted on May 29th and all six surviving until the end of the

year.

Maximum monthly counts (adults + juveniles):

Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec

2+1 2 3 4 4+6 4+6 4+6 4+6 2+6 4+6 7 2+6

GREYLAG GOOSE Anser anser

Five records involving nine birds this year. One on March 3rd and two birds on the 7th with two

again on April 7th, June 1st and from September 8th until the 16th.

GREATER CANADA GOOSE Branta canadensis

One pair bred with an adult first noticed on the nest on April 20th and a brood of six first seen on

May 16th.

Maximum monthly counts:


23 10 13 4 23 113 109 48 354 110 25 24

EGYPTIAN GOOSE Alopochen aegyptiacus

Just a single record of three birds flying over on November 28th.

SHELDUCK Tadorna tadorna

In March single birds on the 11th, 14th and 19th, in May two birds flying over on the 19th and

finally a single bird present on November 3rd.


5

MANDARIN Aix galericulata

A single record of two birds flying over on October 6th.

WIGEON Anas penelope

In April 12 birds were still present on the 2nd dropping down to 2 on the 7th. The first returning

birds were two on July 13th.



164 107 108 12 ---- ---- 2 4 13 51 113 119

GADWALL Anas strepera

Three broods were raised this year.



72 27 30 23 18 42 91 45 24 15 46 53

TEAL Anas crecca

The following records were received. Six on January 17th, one male on February 16th, in March

one on the 3rd, two on the 17th, three on the 24th and 30th and four on the 31st, in April 15 on

the 6th and one on the 8th. In the autumn three on July 11th and two on the 21st, in August 5

on the 25th, in September one on the 7th and eight on the 30th, in October seven on the 19th, in

November two on the 3rd and six on the 19th and in December three on the 17th.



6 1 4 15 ---- ---- 3 5 8 7 6 3

MALLARD Anas platyrhynchos

Seven broods raised this year with two in April, three in May, one in June and one in July.



4 4 14 10 15 7 2 6 7 5 6 7

PINTAIL Anas acuta

Three records this year consisting of nine birds. Two males on February 8th, three males and two

females on March 14th and two birds on September 22nd.


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SHOVELER Anas clypeata

Recorded in every month this year. In April 40 were present on the 3rd with just four on the 14th

and two on the 21st. In May three males were seen on the 10th and 11th with a single bird present

on the 12th. The first returning bird was a male present from June 26th.



18 15 46 40 3 1 2 24 45 13 16 32

POCHARD Aythya farina

As with Shoveler recorded in every month this year. Three were still present on April 24th with a

single male seen on May 23rd.

Monthly maximum counts:


53 8 16 3 1 18 158 200 150 10 14 31

TUFTED DUCK Aythya fuligula

No breeding this year.



60 114 124 80 40 40 169 286 107 59 47 88

SCAUP Aythya marila

The female remained from December 2012 until January 11th. There was one new bird in 2013, a

male present on April 28th.


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GOLDENEYE Bucephala clangula

In January two on the 27th and one on the 28th and 29th, in February one on the 3rd, two

female/1st winters on the 9th, 10th, 16th and 17th with one male and four female/1st winters

on the 18th. In March a pair on the 10th and three on the 16th, 17th and 20th, in April a female

was present from the 7th until the 14th. The first returning bird was a single on October 27th, in

November two juveniles on the 13th, a pair on the 20th, a female on the 24th, 25th with two on

the 27th and one again on the 28th.



2 5 3 1 ---- ---- ---- ---- ---- 1 2 1

RED-BREASTED MERGANSER Mergus serrator

After a two year absence this species returns to the Hilfield year list with a male seen on April 3rd.

GOOSANDER Mergus merganser

Three records this year. A female on January 7th, a pair on March 10th and a female flew in and

stayed for eight minutes on October 27th.

RUDDY DUCK Oxyura jamaicensis

In January three birds were present until a cull on the 15th. The cull did not fully achieve its aim

however as two were still present the day after and for the rest of the month and then throughout

the summer until they were last seen on October 1st. No records were received for November or

December.



3 2 2 2 2 2 2 2 2 2 ---- ----


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LITTLE GREBE Tachybaptus ruficollis

Just one brood this year with 3 young noted on June 23rd. The July count includes two

independent juveniles.



2 1 4 3 4 4 5 3 4 5 4 2

GREAT CRESTED GREBE Podiceps cristatus

Seven broods this year with the first noted on July 21st with two more at the end of July and four

more during August.



13 9 13 22 23 26 55 85 100 66 50 20

BLACK-NECKED GREBE Podiceps nigricollis

Please note that Black-necked Grebe is a ‘Schedule 1’ species and is protected by law.

Please follow any on site notices concerning breeding birds.

Two chicks fledged from two different nests. For the first time at the reservoir birds built nests on

the rafts with a total of seven built, and several failed attempts made to build an eighth, but only

one chick was hatched from these with all the other attempts failing. The first chick was noted on

June 20th and the second on July 1st with both birds still doing well into August. The first bird of

the year arrived on February 5th and was seen on four more dates with three birds then present on

the 19th. In March numbers built up with 14 birds present by the end of the month while in April

the highest count was of 19 birds on the 20th. The highest count in May was of 20 birds. In June

19 birds on the 1st down to 15 on the 19th. In July the highest count was of 13 adults plus two

juveniles. In August two adults and two juveniles on the 1st with one adult and one juvenile on the

6th and just the adult left on the 13th. In September an adult on the 19th, in October an adult on


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the 1st, 15th and 25th. In November one from the 5th until the 10th, three on the 12th and 13th,

one from the 15th until the 26th and two on the 30th. In December single birds seen on several

different dates with at least four different adults involved and an adult and a 1st winter were seen

on the 29th.

CORMORANT Phalacrocorax carbo

Recorded throughout the year.



14 5 12 5 3 2 3 9 23 31 7 6

LITTLE EGRET Egretta garzetta

In January one flew over on the 12th, in August one over on the 4th, one repeatedly placing a stick

in a tree on the 8th and one on the dam on the 14th and 15th. Finally one flew over on November

29th.

GREY HERON Ardea cinerea

Records received were as follows. In January four on the 9th, one on the 26th and 27th, in

February two on several dates, in March one on the 10th and several other dates. In April two on

the 7th, one on the 14th, two on the 17th and 20th and one on the 21st, in May one on the 5th,

in June one on the 2nd, 16th and 23rd. In July two on the 21st four on the 24th and two on the

28th, in August four on the 1st, two on the 4th and one on the 10th, in September two on the 1st

and several other dates. In October three on the 4th and one on the 27th, in November two on the

1st, one the 3rd, 10th and 15th and in December three on the 2nd, one on the 8th, three on the

14th and one on the 15th and 29th.



4 2 1 2 1 1 4 4 2 3 2 3


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RED KITE Milvus milvus

In February one on the 2nd, in March one on the 22nd, in April two on the 1st, 2nd and 20th

and one on 11 other dates. In May one on seven dates and two on the 16th, in June four on the

23rd and one on eight other dates, in July one on six dates and in August one on three dates.

In September just a single record of one on the 30th with two seen on October 6th while in

November there were singles on three dates and in December adult birds were seen on three dates

and a juvenile on the 22nd.

SPARROWHAWK Accipiter nisus

Seen throughout the year. One on five dates in January. One on three dates in February, six dates

in March, nine dates in April with two on three dates. One on two dates in May, five dates in

June and four dates in July. In August singles were recorded on five dates and just two dates in

September with two seen on October 6th and singles on four other dates. Single birds were again

recorded on four dates in November and two dates in December.

COMMON BUZZARD Buteo buteo

Single birds were recorded on six dates in January, in February three on the 16th, two on the 17th

and singles on three dates, in March four on the 14th, a pair on five dates and singles on 3 dates.

In April a mating pair in the southeast woods on the 6th, four birds were seen on five dates and

one or two on 12 other dates, in May four on the 31st, three on the 18th and 26th, two on the

7th and singles on 12 other dates, in June a juvenile was giving hunger calls from the castle lake

trees on the 30th while six were seen on the 8th with one or two on 13 other dates. On July 31st

a home bred juvenile was seen flying strongly and two juvenile were seen flying with an adult on

August 8th and three juveniles with an adult on the 18th. In September five birds on the 20th,

four on the 1st and 24th and three on the 30th, in October three seen on the 6th and a total of

nine birds were seen soaring together on the 7th. In November three on 3rd, two on the 10th and

singles on 11 other dates, in December four on the 15th, two on the 6th and 14th and singles on

four other dates.


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KESTREL Falco tinnunculus

Recorded throughout the year. There was a failed breeding attempt in the south bank nest box.

Four birds were noted on April 20th and 21st.

HOBBY Falco subbuteo

First record of the year was of a single bird on April 28th followed by two on May 5th and singles

on the 11th, 12th and 15th and 16th and 29th. A single bird was seen on June 2nd with two on

the 3rd and a single again on July 28th with singles again on August 17th and 26th. In September

single adults on the 1st, 10th, 12th, 15th and 21st, an adult with a juvenile on 22nd, and adult

on the 24th, an adult with two juveniles on the 26th and 27th, an adult making a food pass to

a single juvenile on the 28th, an adult on the 29th and two juveniles on the 28th and finally two

juveniles on October 1st and one on the 4th.

PEREGRINE Falco peregrinus

Eight records this year. An adult landed on the southwest pylon on February 22nd, in May an adult

on southeast pylon on the 17th, one flew low over the reservoir on the 18th and two adults were

present together on the 30th. In June one on the 3rd, in October one flew around the reservoir

for 15 minutes on the 27th and one was seen briefly on the 29th and finally one was seen on

November 5th.

RED-LEGGED PARTRIDGE Alectoris rufa

Four records this year. Two on the dam embankment on March 27th, two on April 10th and 20th

and two on November 10th.

PHEASANT Phasianus colchicus

Five breeding attempts this year with two of them failing. Records received as follows. In January

one on the 1st and four on the 2nd and 13th, in February two on the 9th, five on the 14th and

two again on the 17th, in March two on the 24th. In April four on the 7th, three on the 9th, 14th

and 17th and four again on the 20th and 21st. In May two on the 26th and two tiny fledglings


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were noted on the 29th while two other breeding attempts failed this month. In June four on the

23rd with a second brood of juveniles noted on the 18th with a third brood noted August 7th. In

September eight juveniles were seen together on the 14th and in November two adults were seen

on the 3rd.

WATER RAIL Rallus aquaticus

In January singles on the 9th, 13th, 17th and 27th, in March one heard on the 10th, in April

one on the 7th and 19th and 26th and the last spring record was of one on May 16th. The first

returning bird was one under the hide on September 9th with one then seen on the 24th. In

November singles on the 24th and 27th and in December one on the 2nd, 3rd, 4th, 5th, 7th and

8th with two on the 17th and 18th and one again on the 19th.

MOORHEN Gallinula chloropus

Five broods this year, two in June and July and one in August.



3 4 6 4 1 2 2 5 10 4 1 3

COOT Fulica atra

A total of 19 broods this year the same as last year. The first brood was noted on May 31st

followed by another ten in June with eight in July.



50 40 40 75 47 130 241 143 115 165 194 234

OYSTERCATCHER Haematopus ostralegus

Recorded on six dates this year. One on one of the rafts on March 22nd, single birds present on

April 9th and 18th and two on the dam on May 6th and June 4th and again on August 3rd.

LAPWING Vanellus vanellus

In January 106 flew over on the 1st with 23 over on the 13th, in February 110 over on the 19th

and eight on the 24th, in March three flew over on the 10th and 17th. There were three birds on

the dam on April 28th while in May one was seen on the 12th with three on the dam on the 5th

and 18th. Five birds were on the dam on July 6th and the next and last record was of three on

December 22nd.

DUNLIN Calidris alpina

Five records this year. One on the dam on January 19th, one seen on March 10th and 24th, one

flew over on May 11th and a juvenile was on the dam on October 12th.


13

COMMON SNIPE Gallinago gallinago

Just the one record of a single bird on the south bank on January 2nd.

WOODCOCK Scolopax rusticola

In January one in the north pines on the 6th and one by the east fountain on the 12th, in February

one in the ESE woods on the 11th, in March in north bank scrub on the 5th and one in the ESE

woods on the 30th. The last first winter period record was of two on the north bank on April 10th.

The only second winter period record was of two or possibly three birds in the north pines on

November 15th.

WHIMBREL Numenius phaeopus

On April 21st two were seen flying over before landing in Pages farm field where they stayed for a

short while before flying off south at 2.15pm.


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CURLEW Numenius arquata

One record of two birds circling the reservoir from 7am until 8am on April 17th.

REDSHANK Tringa tetanus

One on the dam on April 11th, one on June 16th and singles on the dam on July 10th and 19th.

GREEN SANDPIPER Tringa ochropus

One on April 21st first flushed along the north bank and then seen along the dam.

COMMON SANDPIPER Actitis hypoleucos

Seen on 91 dates this year. The first record was of one on March 10th followed by another single

on April 14th. Birds were recorded on 16 dates in April with four on two dates and three also on

two dates. Seen on 13 dates in May with two on four of those days. Three were on the dam on

June 30th and birds were seen on 17 dates in July with four on the 26th. In August recorded on 21

dates with four on the 8th and in September recorded on 22 dates with three on the 5th and the

last record was of a single bird on the 26th.

GREY PHALAROPE Phalaropus fulicarius

A juvenile/first winter bird was present on October 28th and 29th and was the first record since

2008.

MEDITERRANEAN GULL Ichthyaetus melanocephalus

Recorded on 50 dates this year. In January an adult and a 1st winter on the 1st, two adults on the

2nd, one adult on the 3rd, a 1st winter on the 6th, 7th and 25th and an adult and 1st winter on

the 26th. In February a 1st winter on the 5th, 6th, 8th and 11th, two adults and a 1st winter on

the 16th, 17th and 18th, one adult on the 19th, two 1st winters on the 21st and a single adult

on the 22nd. In March an adult on the 1st, 3rd, 10th, two adults on the 11th and three adults

together on the 12th and an adult was present on April 5th. There were no more records until

September when a 1st winter was seen on the 23rd, a 2nd winter, two 1st winters and a juvenile

on the 25th, an adult and 1st winter on the 26th and one 1st winter on the 28th. In October an

adult was present on the 1st, a 1st winter on the 4th and 5th, two 1st winters on the 6th, an adult

on the 15th, 1st winter on the 17th, adult again on the 18th and two adults on the 19th, one

adult and 2nd winter on the 22nd, 2nd winter on the 23rd, adult on the 25th, two adults on the

26th, adult again on the 27th, adult and 2nd winter on the 29th and two adults on the 30th. In

November a 2nd winter was present on the 2nd, an adult on the 10th, 13th and 16th, an adult

and 1st winter on the 24th and an adult on the 26th, 27th and 28th. In December an adult on the

1st, 3rd, 5th, 8th,10th, 12th, 13th and 24th and an adult and 2nd winter on the 29th.

LITTLE GULL Hydrocoloeus minutus

In March three adults on the 7th, four on the 8th, one on the 10th, a 1st winter on the 11th an

adult again on the 25th. In May a single adult on the 12th and 13th and in October a 1st winter on

the 12th and 13th.


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BLACK-HEADED GULL Chroicocephalus ridibundus

The first signs of breeding were noted on March 2nd with two females begging for and receiving

food. Five broods were noted by the end of May and there were 19 broods by the end of June with

the first flying juvenile noted on the 24th. A white adult was recorded on seven dates in January

and six in February and on the 2nd and 10th of March, October 24th, November 13th, 16th, 19th

and 30th and December 6th, 12th, 13th and 15th. In March 910 passage birds were counted on

the 28th mostly consisting of 1st winters and then further spring passage in April consisted of 971

on the 2nd, over 1000 on the 5th and 800 on the 10th again consisting of mainly 1st winters. On

January 22nd 8000+ were present and 3000 on March 11th.

COMMON GULL Larus canus

The following counts were received. There was 500 0n January 26th, 800 on February 2nd with

1000 on the 24th, 300 on March 16th and 30th, 20 on April 8th, eight on October 6th and 13 on

December 15th.


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LESSER BLACK-BACKED GULL Larus fuscus

The following counts were received. There was 500 0n January 26th, 800 on February 2nd with

1000 on the 24th, 300 on March 16th and 30th, 20 on April 8th, eight on October 6th and 13 on

December 15th.

HERRING GULL Larus argentatus

The following counts were received. In January 397 on the 28th, 500 on February 2nd, 136 on

September 5th with 100 on the 24th and 630 on November 9th.

GREAT BLACK-BACKED GULL Larus marinus

In January an adult on the 1st, two immature birds on the 3rd and an adult again on the 11th and

31st, an adult on February 3rd and two immature birds on March 17th with an adult on the 27th.

KITTIWAKE Rissa tridactyla

A 1st winter was in the gull roost on December 31st.

SANDWICH TERN Sterna sandvicensis

Two adults were present for at least an hour on August 26th. This species was last seen in 2010

and is not an easy species to connect with at Hilfield.

COMMON TERN Sterna hirundo

There were nine breeding pairs this year with six broods raised. The first brood was noted on June

29th with the second the next day, three more in July and the sixth on August 6th. The first flying

juvenile was noted on July 28th. The first record of the year was of three birds on April 13th with

the highest April count being 20 on the 16th. Highest count in May was of 45 on the 15th with

28 on the 17th and 22 on the 22nd. Highest count in June was of 26 on the 15th. Five birds were

preent on August 25th and the last record of the year was of a juvenile on September 1st.

ARCTIC TERN Sterna paradisaea

Two records this year with at least two birds present on April 16th and one present on the 17th.

LITTLE TERN Sternula albifrons

No records this year.

2012: As well as the bird seen on May 2nd there was an additional record of one flying high north

at 10.30am on April 23rd.

FERAL PIGEON Columba livia

Regularly seen throughout the year.


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STOCK DOVE Columba oenas

Under recorded but usually present around the castle area. The following records were received.

Two on January 13th and 27th, one on February 17th, two on March 10th and 24th, two on

four dates in April, one on May 12th and five on the 26th with two of them being pulli. One on

September 26th, 50 on October 8th and 10th, one on November 10th and December 1st and 8th.

WOOD PIGEON Columba palumbus

Resident and seen on every visit to the reserve. The only count received was of 80 on November

3rd.

COLLARED DOVE Streptopelia decaocto

Three records this year. One on February 24th, one over on May 19th and one on June 2nd.

RING-NECKED PARAKEET Psittacula krameri

Recorded in every month. In January 18 flew over to roost on the 5th with nine in the reserve on

the 26th and eight on the 27th. In February 12 flew to roost on the 28th while in March five on

the 30th was the highest count. Highest in April was 10 on the 13th, seven on the 1st in May

while birds were only heard in June. Two were seen on July 13th with nine flying south on August

3rd and seven seen on September 22nd. In October 32 flew to roost on the 5th, nine to roost on

November 30th and six birds present on December 3rd and 6th.

CUCKOO Cuculus canorus

Just the one record of a bird perched in a tree on the west bank on June 26th.

BARN OWL Tyto alba

A good run of records from February to May. In February a single bird on the 11th, 19th, 22nd

and 23rd with two on the 24th and the single bird again on the 27th. In March two on the 10th

and one on the 12th, in April one on the 11th and 19th and finally one on May 26th. Two of

these sightings involved a bird roosting in the northeast woods with the other sightings all of birds

hunting.

LITTLE OWL Athene noctua

One was seen near the garages on November 9th and then heard by the castle on the 30th.

COMMON SWIFT Apus apus

One on April 24th was the first of the year, nine days later than last year. By April 28th 100 birds

were present and in May 400 were seen on the 8th, 10th and 12th with 500 on the 15th with at

least two partial white birds seen in these flocks. In June 200 were present on 11th and 100 on

the 23rd with the only July record received being of 10 birds on the 28th. In August 11 on the

10th, one on the 11th and two on the 17th and the last record of the year was a single bird on

September 8th.


18

KINGFISHER Alcedo atthis

Recorded on 12 dates this year. All records were of single birds recorded on the following dates.

January 13th and 16th, February 9th, March 5th, August 29th, September 8th, 26th and 29th,

October 4th, November 5th, 20th and finally December 19th.

GREEN WOODPECKER Picus viridis

Resident. Recorded from April to December, with a maximum of 6 birds together on August 6th.

GREAT SPOTTED WOODPECKER Dendrocopos major

Resident. Recorded from February to December, usually 1 to 2 birds, with 3 in December, and 4 in

February. Four juveniles were ringed in July.

WOODLARK Lullula arborea

There was one record of a Woodlark on March 15th, viewed in Pages Farm from the viewing

platform overlooking Hilfield Park Reservoir. This species was previously last recorded on the reserve

in 1955.

SKYLARK Alauda arvensis

There were seven records, between February and April, June and November. Usually single birds, or

recorded as heard, most often singing over the aerodrome.

SAND MARTIN Riparia riparia

The first birds of the year were singles recorded on 10 March, one flying north, another a very tired

looking bird by the dam wall. Again a single on 11 March, in the snow. Records in April reached

c50 birds on 14th. A single bird was reported in June, and eight birds in August. There were c200

birds on 15 Spetember, with the last record being three birds on 22 September.

SWALLOW Hirundo rustica

The first birds of the year were five on April 15, followed by seven on the 16th. April records

continued to be plentiful, with a maximum of c200 on 19th. Swallows were recorded on several

dates in May, with c300 on 15th. There was a single bird recorded on June 2nd. One juvenile bird

was caught and ringed on August 25th, as part of normal ringing activities. There were autumn

records of c100 on 9th, five birds on September 15th, with the last record of 100 on September

22nd.

HOUSE MARTIN Delichon urbicum

The first bird of the year was a single recorded on April 13th. Subsequent April records were two

on 16th, and 20 on 17th. In May records of c200 birds were recorded on 11th and 15th. Two

juveniles were caught and ringed on September 22nd. Autumn passage in September included

c500 birds on 15th, with the last record being 100 birds on 22nd.


19

MEADOW PIPIT Anthus pratensis

Winter records were received for March and December, with a maximum of 10 on March 28th, and

four reported on a few dates 8-15 December. There was one spring record of four birds on April

8th. Autumn passage was recorded from September 15th, with a maximum of c20 birds on the

22nd. Meadow Pipits were well recorded throughout October and November, with maxima of 19

birds on October 6th and 10 on November 3rd. The last November record was of six birds on the

29th. There were increased ringing efforts and success for this species in 2013, with 49 birds ringed

between September and December, 46 of which were first-year birds.

ROCK PIPIT Anthus petrosus

Five records were received, with one bird recorded on the dam on March 31st and April 1st, and

then three autumn records of two birds on 27th, and 1 bird on September 28th and 29th.

YELLOW WAGTAIL Motacilla flava

There were single birds recorded regularly from April 16th, with two recorded on Pages Farm

on April 22nd. There was one record each of single birds for May and June, on 5th and 16th

respectively. Autumn records were of single birds on September 22nd and 30th.


20

GREY WAGTAIL Motacilla cinerea

Between one and three birds were recorded in every month except December. In January singles

were recorded on 20th and 23rd. In February singles recorded on 21st, 23rd and 24th. In March

one or two birds were recorded on ten dates, with three birds on 29th and 31st. April recorded one

to two birds on 14 dates, including one adult male trapped and ringed on April 7th, and three birds

sighted on 1st, 8th, 13th and 20th. May recorded one bird on 1st and two on 7th. June received

one record of two birds on the 5th. Single birds were recorded on July 9th and August 27th, then

one bird on September 15th and 28th and two birds on September 22nd. there were records of

single birds on four dates in October, and a final record of one bird on November 3rd.

PIED WAGTAIL Motacilla alba yarellii

Resident. Pied Wagails are regularly seen along the dam and breed on the bridge. The first juvenilles

are recorded as beginning to fledge on May 25th, eventually numbering five juvenilles. A record for

June 2nd of 12 birds included eight juveniles. A second brood was recorded being fed under the

bridge on June 29th and subsequently fledging from there on July 13th.

WHITE WAGTAIL Motacilla alba alba

There was only one record this year of a single bird at Pages Farm on March 13th.

WHITE/PIED WAGTAIL Motacilla alba

There were 11 other records of Pied/White Wagtails. March through May recorded one to four

birds, with the peak counts of four being on March 10th and April 9th and 20th. In Septemeber

one bird was recorded on the 3rd. In November two birds were recorded on 3rd, and three on

10th.

WAXWING Bombycilla garrulus

There were two records of birds flying over the reservoir in 2013: a flock of 50+ flying east over the

south bank on January 6th, and six birds flying north-west on March 21st.

WREN Troglodytes troglodytes

Resident. Twenty-eight juvenile birds were ringed between May and August.

DUNNOCK Prunella modularis

Resident. Twelve juvenile birds were ringed between May and August, with a further seven juveniles

ringed in September and November. A maximum of six birds were recorded on 2 June.

ROBIN Erithacus rubecula

Resident. Seventeen juvenile birds were ringed between May and August, with a further ten

juveniles ringed in September.

BLACK REDSTART Phoenicurus ochruros

There was one well recorded bird present from November 29th to December 9th. It was seen

mainly around the pumphouse and on the dam. The bird was trapped and ringed on December


21

8th, and proved to be a first-year female. A record of a bird was also received for November 7th,

from a private site adjacent to the reserve.

WHEATEAR Oenanthe oenanthe

One to three birds were recorded almost daily throughout March, from 24th until April 6th. On

April 31st two birds were trapped and ringed, both identified as second-year males.There were two

birds recorded on April 13th and 26th, and one bird on May 3rd-4th. The bird recorded on May

4th was reported as the Greenland race O. o. leucorhoa, and was the last spring record. Autumn

records were of single birds on August 13th, 29th and 30th, and then one bird on the dam on

October 18th and 19th.

BLACKBIRD Turdus merula

Resident. There was only one juvenile bird ringed in the May to August period this year. During that

period at least eight different males and five different females were present, suggesting that several


22

pairs were present but it was a poor breeding season. Seventeen birds were caught and ringed

throughout the whole year, and a further 11 individuals trapped bearing rings from previous years.

FIELDFARE Turdus pilaris

Double-figure counts were recorded in five winter months: 12 birds on January 3rd, 70 on February

10th and 30 on February 11th, c20 birds recorded on March 24th and 25 on March 28th, then

12 birds on November 10th and 41 on November 28th, 75 on December 12th and 21 birds on

December 29th.

SONG THRUSH Turdus philomelos

Resident. There was one significant count of a flock of c20 birds in bushes on October 17th. There

were three juvenile birds ringed between May and August. During this period there were also four

males and three females trapped. Thirteen birds were caught and ringed throughout the whole

year, and a further five individuals were trapped bearing rings from previous years.

REDWING Turdus iliacus

Redwings were recorded in good numbers in both winter periods and during the autumn. There

were maximum counts recorded of: 15 birds in January, 6 in February, 30 in March, 35 in October,

c30 in November and c100 in December. Single birds were recorded on April 7th and September

1st. Forty-nine birds were ringed during December, 44 of which were first-year birds.

MISTLE THRUSH Turdus viscivorus

Resident. There were records of five birds in January and February, two to four in March, one to

three in April, three on the dam on July 28th, five birds on November 10th, and one on December

7th.

CETTIS WARBLER Cettia cetti

A female was caught and ringed as part of normal ringing activities on the south bank of the

reservoir on April 28th.

GRASSHOPPER WARBLER Locustella naevi

There was one record of a bird reeling near to the viewing platform on April 19th.

SEDGE WARBLER Acrocephalus schoenobaenus

Four birds were seen on April 21st with another single on the 28th. Five juvenile birds were ringed

between May and August, along with three adult birds and one of indeterminate age. Two birds

ringed elsewhere in the UK were also trapped and recorded as part of regular ringing activities (see

more information on these birds in the Ringing Report).

REED WARBLER Acrocephalus scirpaceus

The first bird was recorded on April 24th. The last record was of six birds on August 6th. A total of

62 Reed Warblers was ringed between May and August, 26 of which were juveniles. A further five

juveniles were ringed in September. During the May-August period another 24 returning individuals


23

were caught, including one originally ringed elsewhere in the UK (see more information in the

Ringing Report).

GARDEN WARBLER Sylvia borin

The first record of the year is of one bird on April 28th. There were sightings through May and

June, with a maxima of three singing males on May 7th. The only juvenile was ringed between May

and August, though three different adult birds were ringed between April 28th and June 2nd. The

last record is of a single bird seen on September 13th.

BLACKCAP Sylvia atricapilla

The first record of the year was of a male on April 14th. Birds were regularly recorded between

April and June, with a maximum of 20 birds on April 20th. The last record is of five birds on

September 27th. Between May and August 30 juveniles and 30 adults were ringed (11 male, 18

female, one unsexed). A further 30 juveniles were ringed in September. Only one returning ringed

bird was re-trapped this year, in April. One bird ringed elewhere in the UK was trapped during

regular rinigng activities (see more information in the Ringing Report).

LESSER WHITETHROAT Sylvia curruca

There was one sight record of a single bird on August 25th. Three birds were ringed this year – an

adult female in July, and two juveniles in August.

WHITETHROAT Sylvia communis

The first bird was recorded on April 21st. There were two or three birds present thereafter

throughout April and June, with the last record being eight birds on June 23rd. Thirty-five juvenile

birds were ringed between May and August. Nine adult individuals were also ringed in this period,

and a further seven had been ringed in April (eight were female, four male, and four unsexed).

Two returning birds were re-trapped this year in April and June, both males. These ringing records

suggest at least six breeding pairs were on site this year.

WOOD WARBLER Phylloscopus sibilatrix

There was one record of a single bird trapped and ringed as part of normal ringing activities on the

north bank on April 18th. This is the first record since 2001.

CHIFFCHAFF Phylloscopus collybita

The first bird recorded was on 10 March. Birds were then recorded from March until 30 June, with

a maximum of 20 birds present on 20 April. Thirty-three juveniles were ringed between May and

August, with a further 16 juveniles ringed in September. Three birds were recorded on August

6th, five on September 22nd and two on September 27th. One bird was recorded on November

1st, with a bird ringed on November 7th, these records representing either very late last passage

records, or wintering bird(s).

WILLOW WARBLER Phylloscopus trochilus

The first birds were recorded on April 7th, when three were present. Records were received for

seven dates in April, with five birds on April 16th and one to three on other dates. A bird was heard


24

on June 16th. Five juveniles were ringed in August (two of these on the 18th). There were two

autumn sight records, each of a single bird, on August 25th and September 8th. Three juvenile

birds were ringed in September, the latest on the 12th, which represented the last record for the

year.

GOLDCREST Regulus regulus

Resident. Records were received across the year. Eighteen birds were ringed this year, including ten

juveniles trapped between September and November.

FIRECREST Regulus ignicapilla

There was one record of a bird trapped on the north bank on April 14th.

LONG-TAILED TIT Aegithalos caudatus

Resident. Significant counts include: 12 birds on January 1st, eight on March 10th, and 40 plus

on November 1st. A record was received of a chick being fed on May 16th. Twelve juveniles were

caught during May to August.

BLUE TIT Cyanistes caeruleus

Resident. Breeds in good numbers around the reserve. A total of 182 nestlings was ringed from the

nest boxes. Data from the ringing group gave some peak winter numbers of c30 birds in November

and c50 in December (a combination of birds caught and others sighted, generally around the

feeder site).

GREAT TIt Parus major

Resident. Breeds in good numbers around the reserve. A total of 60 nestlings was ringed from the

nest boxes. Data from the ringing group gave some peak winter numbers of c20 birds in November

and c18 in December (a combination of birds caught and others sighted, generally around the

feeder site).


25

COAL TIT Periparus ater

Resident. Breeds in small numbers. There were six sight records of one or two birds in the winter

months from November to February. Five birds were ringed in 2013 (including one juvenile in July),

and a further three birds caught.

NUTHATCH Sitta europaea

Resident. There were eight sight records of single birds. Two birds were ringed in 2013 (one a male,

the other unsexed), and another female bird re-trapped.

TREECREEPER Certhia familiaris

Resident. There were 11 sight records of one to two birds in the winter months from November to

February. Six birds were ringed in 2013, and a male bird ringed in a previous year was caught.

JAY Garrulus glandarius

Resident. Significant sightings include counts of five and eight birds on April 7th and 21st

respectively, and five birds on November 10th. One juvenile bird was ringed in September.

MAGPIE Pica pica

Resident. There were sightings throughout year, with 18 birds present on December 29th.

JACKDAW Corvus monedula

Possibly breeding. Recorded regularly in the spring months, March through June. A pair were

recorded nest building in a cavity in the castle on April 10th, and three birds were seen in and

around the cavity on May 5th and 13th. Autumn and winter counts included maxima of six birds in

September, 15 in October and 20 in December.

ROOK Corvus frugilegus

There were two records for this species this year: a single bird flew over on February 16th, and 12

birds were sighted on April 20th.

CARRION CROW Corvus corone

Resident. Breeds locally. Two to four birds were seen regularly, often around the dam.

RAVEN Corvus corax

There was one record of a single bird seen flying south over the reservoir on January 9th.

STARLING Sturnus vulgaris

There were two spring records of two birds sighted on June 2nd and one bird on June 23rd. There

were autumn/winter sightings of 40 birds on November 10th and c200 on November 19th.


26

CHAFFINCH Fringilla coelebs

Resident. All the counts come from the ringing group, and include ringed and sighted individuals.

There were significant counts of 20 birds on February 17th, 15 on March 10th and 20 on March

28th, then one to five birds were recorded on 14 other dates in April to June, September,

November and December. Twenty-eight birds were ringed in 2013, including three juveniles in

September, and a further three birds caught.

GREENFINCH Carduelis chloris

Resident. Sight records were received between January and March. Three birds were ringed this

year, two of which were juveniles, ringed in September.

GOLDFINCH Carduelis carduelis

Resident. A total of 63 birds was ringed this year, including four juveniles ringed between May and

August. The maximum number of birds recorded at any one time was of c15 birds on July 11th.

SISKIN Carduelis spinus

Records were received for January, February and March. The maximum recorded was five birds on

February 24th. Ten birds were ringed this year.

LINNET Carduelis cannabina

One bird was recorded on November 3rd.

LESSER REDPOLL Carduelis cabaret

There were four records of 1-2 birds in January, February and April. Six birds were seen on October

31st. There were three November records, with a maximum of three birds on two of the dates. Four

December records included a maximum of 21 birds on the 17th. Seven birds were ringed in 2013.

BULLFINCH Pyrrhula pyrrhula

Resident, but in declining numbers. One to two birds were recorded in February through April, July

and December, with three birds recorded on January 13th. Three birds were ringed this year.

REED BUNTING Emberiza schoeniclus

Resident and breeds on site. Six birds were recorded on January 9th, then one to three in other

months. Eleven birds were ringed this year, including seven juveniles between May and August.

ESCAPE

MONK PARAKEET Myiopsitta monachus

One was heard and seen well perched on May 5th, the first record since 2009.

Mark McManus and Eirwen Edwards


27

BIRDS – YEAR BY YEAR REVIEW

Year 13 12 11 10 09 08 07 06 05 04 03 Last seen

Mute Swan l l l l l l l l l l l

Bewick’s Swan l l

Whooper Swan l l

White-fronted Goose l l

Greylag Goose l l l l l l l l l l l

Canada Goose l l l l l l l l l l l

Brent Goose l l l

Egyptian Goose l l l l l l

Shelduck l l l l l l l l l l l

Mandarin l l l l l l l l l

Wigeon l l l l l l l l l l l

Gadwall l l l l l l l l l l l

Teal l l l l l l l l l l l

Mallard l l l l l l l l l l l

Pintail l l l l l l l l l

Garganey l l l l

Blue-winged Teal 1998

Shoveler l l l l l l l l l l l

Red-crested Pochard l l l l l l l

Pochard l l l l l l l l l l l

Ring-necked Duck 2001

Ferruginous Duck 1961

Tufted Duck l l l l l l l l l l l

Scaup l l l l

Eider 1963

Long-tailed Duck 1985

Common Scoter l l l l l l

Velvet Scoter 1976

Goldeneye l l l l l l l l l l l

Smew l l l l l

Red-breasted Merganser l l l

Goosander l l l l l l l l l l l

Ruddy Duck l l l l l l l l l l l

White-headed Duck l l l

Red-legged Partridge l l l l l l l l l

Grey Partridge 1960

Pheasant l l l l l l l l l l l

Red-throated Diver 1965

Black-throated Diver 1967

Great Northern Diver l


28

Year 13 12 11 10 09 08 07 06 05 04 03 Last seen

Little Grebe l l l l l l l l l l l

Great Crested Grebe l l l l l l l l l l l

Red-necked Grebe l l

Slavonian Grebe l

Black-necked Grebe l l l l l l l l l l l

Leach’s Petrel 1983

Cormorant l l l l l l l l l l l

Shag l

Bittern l l l

Little Egret l l l l l l l l

Grey Heron l l l l l l l l l l l

Honey Buzzard l

Red Kite l l l l l l l l l l l

Marsh Harrier l l

Sparrowhawk l l l l l l l l l l l

Buzzard l l l l l l l l l l l

Osprey l l l l l l

Kestrel l l l l l l l l l l l

Merlin 1979

Hobby l l l l l l l l l l l

Peregrine l l l l l l l l

Water Rail l l l l l l l l l l l

Spotted Crake 1967

Moorhen l l l l l l l l l l l

Coot l l l l l l l l l l l

Oystercatcher l l l l l l

Avocet l l

Little Ringed Plover l l l l l l l l l l

Ringed Plover l l l l l l l l

Golden Plover l l l l l

Grey Plover 2001

Lapwing l l l l l l l l l l l

Knot l

Sanderling l l l l

Little Stint l

Curlew Sandpiper l

Dunlin l l l l l l l l l l

Ruff l

Jack Snipe 1996

Snipe l l l l l l l l l l l

Woodcock l l l l l l l l

Black-tailed Godwit l

Bar-tailed Godwit 2001


29

Year 13 12 11 10 09 08 07 06 05 04 03 Last seen

Whimbrel l l l l l l l l

Curlew l l l l l l l

Spotted Redshank l

Redshank l l l l l l l l l l l

Greenshank l l l l l l l l l l

Green Sandpiper l l l l l l

Wood Sandpiper l

Spotted Sandpiper l

Common Sandpiper l l l l l l l l l l l

Turnstone l l l

Grey Phalarope l l

Long-tailed Skua 1988

Mediterranean Gull l l l l l l l l l l l

Laughing Gull l

Little Gull l l l l l l l l l l l

Sabine’s Gull 1988

Black-headed Gull l l l l l l l l l l l

Common Gull l l l l l l l l l l l

Lesser Black-backed Gull l l l l l l l l l l l

Herring Gull l l l l l l l l l l l

Yellow-legged Gull l l l l l l l l l

Glaucous Gull 1980

Great Black-backed Gull l l l l l l l l l l l

Kittiwake l l l l l l l

Sandwich Tern l l l l

Common Tern l l l l l l l l l l l

Arctic Tern l l l l l l l l l l

Little Tern l l l l

Black Tern l l l l l l l l l l

White-winged Black Tern 1970

Little Auk 1995

Feral Pigeon l l l l l l l l l l l

Stock Dove l l l l l l l l l l l

Wood Pigeon l l l l l l l l l l l

Collared Dove l l l l l l l l l l

Turtle Dove 2001

Ring-necked Parakeet l l l l l l l l

Cuckoo l l l l l l l l l l l

Barn Owl l l l l l l l l

Little Owl l l l l l l l l l

Tawny Owl l l l l l l l l l

Short-eared Owl l l l

Swift l l l l l l l l l l l


30

Year 13 12 11 10 09 08 07 06 05 04 03 Last seen

Alpine Swift 1990

Kingfisher l l l l l l l l l l

Hoopoe 1973

Green Woodpecker l l l l l l l l l l l

Great Spotted Woodpecker l l l l l l l l l l l

Lesser Spotted Woodpecker l l l l l l

Woodlark l

Skylark l l l l l l l l l l l

Sand Martin l l l l l l l l l l l

Swallow l l l l l l l l l l l

Red-rumped Swallow 2000

House Martin l l l l l l l l l l l

Tree Pipit l

Meadow Pipit l l l l l l l l l l l

Rock Pipit l l l l l l

Water Pipit 1992

Yellow/Blue-headed Wagtail l l l l l l l l l l

Grey Wagtail l l l l l l l l l l l

Pied/White Wagtail l l l l l l l l l l l

Waxwing l l l

Wren l l l l l l l l l l l

Dunnock l l l l l l l l l l l

Robin l l l l l l l l l l l

Black Redstart l l l l l

Redstart l l

Whinchat l l

Stonechat l l l l l

Wheatear l l l l l l l l l l l

Ring Ouzel 1993

Blackbird l l l l l l l l l l l

Fieldfare l l l l l l l l l l l

Song Thrush l l l l l l l l l l l

Redwing l l l l l l l l l l l

Mistle Thrush l l l l l l l l l l l

Cetti’s Warbler l l

Grasshopper Warbler l l l l

Aquatic Warbler 1960

Sedge Warbler l l l l l l l l l l l

Reed Warbler l l l l l l l l l l l

Lesser Whitethroat l l l l l l l l l l l

Whitethroat l l l l l l l l l l l

Garden Warbler l l l l l l l l l l l

Blackcap l l l l l l l l l l l


31

Year 13 12 11 10 09 08 07 06 05 04 03 Last seen

Eastern Crowned Warbler l

Wood Warbler l

Chiffchaff l l l l l l l l l l l

Willow Warbler l l l l l l l l l l l

Goldcrest l l l l l l l l l l l

Firecrest l l l l

Spotted Flycatcher l l l l l l l l

Pied Flycatcher 2000

Bearded Tit 1974

Long-tailed Tit l l l l l l l l l l l

Marsh Tit l

Willow Tit 1994

Coal Tit l l l l l l l l l l l

Blue Tit l l l l l l l l l l l

Great Tit l l l l l l l l l l l

Nuthatch l l l l l l l l

Treecreeper l l l l l l l l l l l

Golden Oriole 1984

Red-backed Shrike 1965

Great Grey Shrike 1970

Jay l l l l l l l l l l l

Magpie l l l l l l l l l l l

Jackdaw l l l l l l l l l l l

Rook l l l l l l l l

Carrion Crow l l l l l l l l l l l

Raven l l l

Starling l l l l l l l l l l l

House Sparrow l

Tree Sparrow 1987

Chaffinch l l l l l l l l l l l

Brambling l l l l l l l

Serin 1973

Greenfinch l l l l l l l l l l l

Goldfinch l l l l l l l l l l l

Siskin l l l l l l l l l l l

Linnet l l l l l l l l l l l

Lesser Redpoll l l l l l l l l l l

Common Redpoll l

Crossbill l

Bullfinch l l l l l l l l l l l

Hawfinch 1982

Snow Bunting 1978

Yellowhammer l l


32

Year 13 12 11 10 09 08 07 06 05 04 03 Last seen

Cirl Bunting 1959

Little Bunting 1960

Reed Bunting l l l l l l l l l l l

Corn Bunting 1984

Escapes 1984

Black Swan 1998

Snow Goose 1997

Pink-footed Goose 1993

Barnacle Goose l

Bar-headed Goose l 1998

Argentine Bluebill 2002

Ruddy Shelduck l 1995

Bahama Pintail l

Marbled Teal 1998

Grey-headed Gull 2002

Monk Parakeet l l l

Grey Cockatiel 2000

Cockatiel 1998

Parakeet Sp. 2001

Double-barred Finch l

Key: l = recorded in that year

Bob Cripps


33

RINGING REPORT FOR 2013

The year started well with reasonable numbers of birds ringed during a mild January. From here on,

the weather turned wet and cold with wildly fluctuating temperatures through February to March.

This resulted in very poor catches at our regular winter feeder site. Only 52 new birds were ringed

from 16 sessions through this period to the end of March.

April started cold at 3°C and fluctuated to 23°C then turning cold again and remaining still very

wet. This turned out to be a disaster for the early nesters. Only 79 birds were ringed from nine

sessions during this month.

There were a couple of notable birds

passing through in April, a first for Hilfield

was a Wood Warbler on the 18th and a

Grey Wagtail on the 7th, caught along

the northern edge of the dam, was the first

since 2004. Another first for ten years was

a Cetti’s Warbler, probably just passing

through, on 28th.

CES (Constant Effort Site) started in the first

week of May, still with very low numbers of

birds being caught, only 20 ringed from the

first three CES sessions, at this south side

site.

June saw more settled weather conditions, although still on the wet side. Numbers ringed at last

started to improve. It was not until the end of June when we started to catch the first young birds

for the year. CES 7 on the 30th June saw 48 birds ringed that day. A bird that is not often seen

here is a Kingfisher which was caught on CES in July, only the third in a number of years. The

north side study of Reed Warblers was a little disappointing this year, with few birds ringed. For

the remainder of the year the birds caught had returned to their usual numbers. Autumn migration

came and went without any noticeable increase in birds.

Another rare bird in December was a Black Redstart, a first since 1996, which had been around the

pumping station for a week before being tempted by mealworms and a tape lure into a spring trap.

The introduction of a new pipit trap and a new tape for Redwings saw a dramatic increase in

these species numbers caught during the autumn and winter period. Meadow Pipits numbered

49, up from 25 the previous year and Redwings totals also 49, up from none in 2012.

The national decline in Greenfinches was mirrored at the Reservoir with just three birds caught all

year compared with 23 in 2012.


34

Compared with 2012, new birds ringed were very similar.

Annual summary 2009 2010 2011 2012 2013

New birds ringed 1066 1377 1715 1188 1264

No. of species 35 45 44 43 47

No. of pulli 330 193 364 217 244

No. of retraps 417 1022 1348 1260 1183

Pulli report

Pulli ringed this year were Blue Tits, Great Tits, Stock Doves.

This year 78 nest boxes were cleared over the winter and early spring period. Of these 42 boxes

were used and 36 were unused. We found that birds from 31 boxes had fledged and 11 nests were

abandoned either at the egg laying stage or during the early fledging period. This is not surprising

given the non seasonal weather and possible shortage of suitable food for the young during the

nesting period.

From the 31 successful boxes, 182 Blue Tits were ringed along with 60 Great Tits.

As of November 2013 the retrap rate of pulli was 28 out of 182 for the Blue Tits, which percentage

wise is just about the yearly average. Great Tits did better with 17 retrapped from the 60 pulli

ringed, which is 28%, a slightly increased percentage from previous years. There must be a certain

amount of dispersal for many of the young which does distort the percentage numbers.

Two Stock Doves were ringed in their usual nest box.

Ringing totals as an indication of population change at Hilfield between 1998 and 2010

Species 1998 2006 2007 2008 2009 2010 2011 2012 2013

Song Thrush 4 12 19 8 25 19 15 17 13

Sedge Warbler 34 7 5 1 9 15 6 12 6

Reed Warbler 91 85 50 59 85 149 114 96 67

Lesser Whitethroat 11 10 6 2 0 8 8 0 3

Whitethroat 26 33 12 9 38 27 55 18 51

Garden Warbler 14 6 12 6 4 6 14 8 4

Blackcap 88 51 60 54 79 87 139 120 101

Chiffchaff 52 21 43 28 34 75 111 55 78

Willow Warbler 19 12 7 4 8 12 9 3 13

Goldcrest 11 7 25 17 7 29 29 45 18

Long-tailed Tit 28 32 47 60 10 42 52 7 34

Reed Bunting 18 8 10 4 5 6 12 9 11

Siskin 0 0 0 0 0 1 8` 28 10

Lesser Redpoll 0 0 0 1 0 9 28 47 7

Goldfinch 11 3 1 4 1 60 101 51 62


35

Song Thrush Little change year-on-year with 13 birds.

Sedge Warbler Better than average numbers with 14 birds, 12 new and 2 controls, one in April

and the other in August. First bird caught 21.04.13 and the last 01.09.13.

Reed Warbler Another poor year with just 67 birds. First bird caught 19.05.13, the last ringed

on 01.09.13 with a last retrap on 08.09.13.

Lesser Whitethroat After no birds in 2012, we had three this year.

Whitethroat A good recovery for these birds with a return to our previous high number.

First bird on 24.4.13, last ringed bird on 18.8.13 with a last retrapped bird on

1.9.13.

Garden Warbler Another low count for this species with just four birds.

Blackcap Similar numbers to previous years with 101 birds, just a little down on the

previous two very good years. First bird was on 14.4.13 and the last bird on

29.9.13. There were no winter Blackcaps caught here in 2013.

Chiffchaff An increase for this bird in 2013 compared with a disappointing previous year.

First bird 7.4.13 and the last 7.11.13 which is possible an over wintering bird.

Willow Warbler A good year for this species with birds seen on spring passage, 10.4.13 to

28.4.13 and autumn passage, 4.9.13 to 12.9.13. There is no sign of local

breeding here.

Goldcrest An average number of birds after last years excellent count.

Long-tailed Tit Another species that has bounced back to average numbers after last

years poor results.

Reed Bunting No real change in the status of these birds with 11 ringed.

0

30

60

90

120

150 MigrantsReed WarblerBlackcapChi�cha�Whitethroat

'13'12'11'10'09'08'07'060

25

50

75

100

'13'12'11'10'09'08'07'06

ResidentsSong ThrushGoldcrestLong-tailed TitReed Bunting


36

Siskin After last year’s excellent results for this bird, numbers were down to just ten

birds which is still very good compared to previous year’s of none.

Lesser Redpoll This bird is well down on the previous good year with just seven birds. There

were two of our retraps from the previous year.

Goldfinch Little change in the numbers from the last four years.

Monthly totals of new birds ringed in 2013

Species Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

Mute Swan 1 4 5

Canada Goose 2 1 3

Water Rail 1 2 3

Moorhen 1 2 2 1 6

Common Sandpiper 3 1 4

Stock Dove 2 2

Woodpigeon 1 1

Swift 1 1

Kingfisher 1 1

Great Sp. Woodpecker 1 4 1 1 7

Swallow 1 1

House Martin 2 2

Meadow Pipit 6 19 19 5 49

Grey Wagtail 1 1

Wren 1 1 2 2 1 16 13 4 1 1 42

Dunnock 1 7 1 1 7 6 4 3 30

Robin 1 1 7 5 5 10 1 1 31

Black Redstart 1 1

Wheatear 2 2

Blackbird 2 1 2 1 4 2 1 4 17

Song Thrush 2 1 3 1 2 1 2 1 13

Redwing 49 49

Cetti's Warbler 1 1

Sedge Warbler 1 2 7 2 12

Reed Warbler 3 7 23 29 5 67

Whitethroat 7 4 15 13 12 51

Lesser Whitethroat 1 2 3

Garden Warbler 1 1 1 1 4

Blackcap 24 6 6 15 19 31 101

Wood Warbler 1 1

Chiffchaff 19 3 15 9 10 21 1 78

Willow Warbler 5 5 3 13

Goldcrest 6 1 1 10 18

Long-tailed Tit 3 2 2 4 9 4 7 3 34


37

Species Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

Coal Tit 1 3 1 5

Blue Tit 2 1 32 155 7 40 54 9 2 302

Great Tit 1 2 7 38 53 15 15 27 2 5 2 167

Nuthatch 1 1 2

Treecreeper 1 1 4 6

Jay 1 1 1 3

Chaffinch 2 3 6 1 4 3 8 1 28

Greenfinch 1 2 3

Goldfinch 7 4 4 1 5 1 1 16 24 63

Siskin 4 3 3 10

Lesser Redpoll 1 1 4 1 7

Bullfinch 2 1 3

Reed Bunting 1 1 5 3 1 11

Grand Total 37 21 31 79 93 281 132 187 183 31 91 98 1264

Total Species 17 11 12 18 12 17 20 22 20 7 15 15

Ringing totals

2013 1994-2013

Species Adults Pulli Adults Pulli

Mute Swan 5 31

Canada Goose 3 13

Wigeon 16

Teal 3

Mallard 49

Ruddy Duck 3

Sparrowhawk 8

Kestrel 3 40

Water Rail 3 39

Moorhen 6 86

Coot 104

Dunlin 1

Common Sandpiper 4 22

Common Tern 39

Stock Dove 2 16

Woodpigeon 1 14

Cuckoo 1

Little Owl 1 14

Tawny Owl 1 2

Swift 1 174

Kingfisher 1 50


38

2013 1994-2013


Green Woodpecker 24

Great Spotted Woodpecker 7 54

Sand Martin 7

Swallow 1 10

House Martin 2 42

Meadow Pipit 49 211

Grey Wagtail 1 7

Pied Wagtail 3 4

Wren 42 590 16

Dunnock 30 445

Robin 31 574

Wheatear 2 7

Black Redstart 1 2

Redstart 2

Stonechat 1

Blackbird 17 338 4

Song Thrush 13 189

Redwing 49 58

Mistle Thrush 6

Grasshopper Warbler 1

Cetti’s Warbler 1 2

Sedge Warbler 12 350

Reed Warbler 67 1573

Lesser Whitethroat 3 101

Whitethroat 51 338

Garden Warbler 4 144

Blackcap 101 1201

Eastern Crowned Warbler 1

Wood Warbler 1 1

Chiffchaff 78 944

Willow Warbler 13 228

Goldcrest 18 309

Firecrest 3

Spotted Flycatcher 2

Pied Flycatcher 1

Long-tailed Tit 34 645

Coal Tit 5 61

Blue Tit 120 182 1869 2483

Great Tit 107 60 1382 995

Treecreeper 6 56

Nuthatch 2 9

Jay 3 75

Magpie 18


39

2013 1994-2013


Carrion Crow 1

Starling 54

Chaffinch 28 222

Brambling 3

Greenfinch 3 79

Goldfinch 63 334

Siskin 10 82

Lesser Redpoll 7 100

Common Redpoll 2

Bullfinch 3 102

Reed Bunting 11 252 5

Ring-necked Parakeet 3

Total numbers 1020 244 13737 3618

Species 47 73 11

Returning ringed warblers

This year saw the return of just one Blackcap from the previous year.

Disappointingly there were only three returning Chiffchaffs caught, after eight returned in 2012.

Only two Whitethroats returned, one from 2012 ringed as a 4 male and another a veteran from

July 2009 which was also ringed as a 4 male.

Reed Warblers did much better for returns with 15 birds, very slightly down on last year. Again they

included some veteran birds. Three were ringed in 2008 and for two of these it was the first time

we had retrapped them since. Of the others one was from 2009, two from 2010, two from 2011

and six from 2012, one of which was a returning Control.

Hilfield north side reed bed

This year we were unable to do as much monitoring of the north side Reed Warblers as we have

done in previous years for various reasons. Of the returning adults, six were found to be nesting

here, all known dedicated north side birds. There were four additional new adult birds ringed here.

Of these ten adults we had four males and four females with two being unsexed. We ringed only

eight juveniles here but there may have been more if we had completed more ringing sessions.


40

Controls and recoveries

The controls and recoveries are arranged by species, with ringing details on the first line and

recovery data on the second.

The following codes have been used:

Age when ringed:

1. pullus (nestling or chick)

3. Hatched during calendar year of ringing, with a 3J In juvenile plumage

5. Hatched during previous calendar year

4. Hatched before calendar year of ringing, but exact year unknown

6. Hatched before previous calendar year, but exact year unknown

Sex: M = male, F = female

Birds ringed elswhere and controlled at Hilfield Park Reservoir

Sedge Warbler Y001406 4 28.07.2011 Icklesham, East Sussex

Controlled 4 21.04.2013 Hilfield Res. Herts

663 day, 109 km, 321 degrees

Sedge Warbler Y855432 3J 27.07.2013 Wicken Fen, Cambs

Controlled 3J 04.08.2013 Hilfield Res. Herts

8 days, 84 km, 210 degrees

Reed Warbler X270953 4M 10.07.2010 Bedfont Lakes, Bedfont, Greater London

Controlled 4 04.08.2013 Hilfield Res. Herts

1121 days, 26 km, NNE

This was a re-trap of a control from 2012.

Blackcap L497646 3F 04.09.2010 Queen Mary Reservoir, Surrey

Controlled 4F 20.06.2013 Hilfield Res. Herts


Lesser Redpoll 317663 3 12.11.2011 Cissbury Ring, Worthing, West Sussex

Controlled 3 02.12.2012 Hilfield Res, Herts


Lesser Redpoll L778192 6 11.02.2012 Mildenhall, Suffolk

Controlled 4 13.12.2012 Hilfield Res, Herts


Siskin 12609259 4M 10.01.2012 Blauberg, Antwerp, Belgium

Controlled 4M 10.10.2012 Hilfield Res, Herts



41

Birds ringed at Hilfield Park Reservoir and recovered elsewhere in 2013

Reed Warbler T675894 3 23.07.2006 Hilfield Res. Herts

4 11.09.2013 Salbura, Vitoria-Gasteiz, Alava, Spain


A good recovery after seven years.

Reed Warbler L768804 3J 07.08.2011 Hilfield Res. Herts

4 01.06.2013 Marston Moretaine, Beds


Reed Warbler X386935 4 27.07.2012 Hilfield Res. Herts

4 07.07.2013 Stanwell Moor, Surrey

350 days, 27 km, SSE

Reed Warbler Y972816 3J 18.08.2013 Hilfield Res. Herts

3J 05.09.2013 Broadwater Gravel Pit, Greater London


Dunnock Y972543 5 05.05.2013 Hilfield Res. Herts

Killed by cat 06.09.2013 Bushey, Herts


Blackcap Y972125 3 16.09.2012 Hilfield Res. Herts

4F 19.05.2013 Skaw, Whalsay, Shetland


Possibly on its southerly migration from Shetland in 2012.

Blackcap Y972110 4M 09.09.2012 Hilfield Res. Herts

5M 16.05.2013 Oriestone Forest, Kent


Goldcrest DJY794 3 28.10.2012 Hilfield Res, Herts

Controlled 3 18.12.2012 Marston Sewage Works, Lincs


Song Thrush RW93878 5 10.04.2013 Hilfield Res. Herts

Found dead, hit window 25.09.2013 Kantens, Eemsmond, The Netherlands


Mike Beatley


42

THE BUTTERFLIES OF HILFIELD PARK RESERVOIR 2013

SMALL SKIPPER Thymelicus sylvestris

Recorded between July 8th and August 20th in significantly higher numbers than the last two

years, being described as quite common during mid-late July.

ESSEX SKIPPER Thymelicus lineola

Careful scrutiny of the salient features revealed the presence of one on July 14th and two on the

28th. Perhaps this species has been overlooked during the previous eight years.

LARGE SKIPPER Ochlodes venata

First seen on June 19th, considerably later than usual. The best count was of 20 on July 8th and the

final two were noted on the 18th.

CLOUDED YELLOW Colias croceus

After a three year absence this eye-catching butterfly bounced back very strongly. Isolated sightings

comprised a male on June 21st and a Helice form female on August 11th. From August 23rd to

September 7th the species was continually present along the dam embankment in good numbers,

with a best count of six on September 5th.

BRIMSTONE Gonepteryx rhamni

Observations on 20 days between April 20th and June 19th constituted a four-fold increase on the

previous year. The best count was of five on May 7th and up to three ovipositing females were seen

on ten dates. Single fresh summer brood specimens found on seven dates between July 8th and

August 25th was also a big improvement on the usual situation.


43

LARGE WHITE Pieris brassicae

Sightings on 23 dates between April 23rd and September 18th was a huge improvement on the

previous year. The best actual count was of five on July 15th, though considerably more than that

seemed to be present in early August.

SMALL WHITE Pieris rapae

Recorded on numerous dates between April 20th and October 17th, with a peak of about 20 on

July 28th.

GREEN-VEINED WHITE Pieris napi

Following the first two on May 1st there was a sharp spike in numbers with at least ten on the 7th.

Subsequently much lower numbers were seen, with the last two on September 22nd.

ORANGE TIP Anthocharis cardamines

The entire flight season was late, ranging from May 1st to June 21st, and numbers peaked at 15 on

May 7th.

PURPLE HAIRSTREAK Quercusia quercus

Once again an evening survey of flight activity around the north monad of the reserve was

undertaken on July 17th. In hot but cloudy conditions 70 were counted between 19:10 and 20:05.

Casual observations of the oak canopy between the east fountain and south-east bay on July 28th

indicated a high density in that area.

WHITE-LETTER HAIRSTREAK Satyrium w-album

Surprisingly there was a further increase in numbers near the east fountain. Sightings between July

9th and 21st peaked at six on the 13th.


44

SMALL COPPER Lycaena phlaeas

Recorded on numerous dates between May 19th and November 10th, with best counts of 25 on

August 7th and 15 on October 7th.

BROWN ARGUS Aricia agestis

The spring brood commenced with one on June 4th and ended with one just four days later. The

late summer brood though was truly exceptional, beginning with five on August 7th. There were

records on a further 16 dates until September 27th with multiple sightings predominating, and a

best count of six on September 5th.

COMMON BLUE Polyommatus icarus

A very good year for this species, which was noted on numerous dates between June 2nd and

September 24th. Counts in June and August were mainly in double figures with an exceptional 69

on August 23rd.

CHALKHILL BLUE Lysandra coridon

Of three species new to the reserve this year this must surely be the least anticipated. A male in

dazzling pristine condition was found near the south-west pylon on July 21st and was still there

the following day. On August 7th a male was found c.300 metres away along the south bank, in

such fresh condition that it could only be a second specimen. Photographic details of a male found

nearby on August 18th suggest the latter two records refer to the same individual.

HOLLY BLUE Celastrina argiolus

One-two were seen on eight dates between May 1st and June 6th. The only evidence of a second

brood concerned one on August 4th.

PURPLE EMPEROR Apatura iris

On July 18th there was a chance encounter with this majestic species when one flew over the oak

canopy near the east fountain; the first record for Hilfield. The next day it became apparent that

two were flying about above the treetops. Two were there again on the 21st and 22nd, when it

seemed likely that two individuals flying in from the adjacent Bio Products site were additional. On

the 24th a superb telescope view of one perched on an oak leaf was obtained and the final record

was of one on the 25th.

RED ADMIRAL Vanessa atalanta

There were records on 14 dates between May 25th and October 24th but the only multiple count

was of three on July 17th.

SMALL TORTOISESHELL Aglais urticae

Seen between April 7th and October 6th with a very large increase in numbers and dates recorded.

The best spring count was of seven on April 23rd. Emergence of the summer brood began on June

27th and peaked at 26 on July 11th.


45

PEACOCK Inachis io

Very low numbers were noted from March 5th to mid-April, after which there was a strong

presence, reaching a peak of 25 on May 1st. The summer brood was also much improved with

a best count of 33 on August 4th, but the last three months of the flight season saw only a few

singletons, the last being on November 15th.

COMMA Polygonia c-album

Noted in every month between March 5th and October 7th, with a best count of eight on July

18th.

SILVER-WASHED FRITILLARY Argynnis paphia

Another major highlight of the year was the discovery of this species on the reserve for the first

time. A single specimen was at the north-east corner, giving exceptionally good views as it nectared

on ragwort flowers on August 23rd.

SPECKLED WOOD Pararge aegeria

There were numerous sightings between May 13th and October 10th, with a huge best count of

32 on September 5th.

MARBLED WHITE Melanargia galathea

Following a late start with one on June 30th numbers were worryingly low well into July, but then

rapidly rose to 113 on July 22nd. The final one was seen on August 7th.

GATEKEEPER Pyronia tithonus

Numbers rose from two on July 15th to being described as abundant on August 4th; apparently an

improvement on recent years. The last two were seen on August 25th.

MEADOW BROWN Maniola jurtina

The main bulk of sightings were between June 19th and September 7th, with a peak of at least a

hundred on July 9th. Most unexpectedly a pristine and exceptionally bright specimen was found on

September 27th and 29th, surely a rare example of a second brood.

SMALL HEATH Coenonympha pamphilus

Not seen since 2006, a single specimen of this previously abundant grassland species was found

near the boathouse on June 26th and 27th.

RINGLET Aphantopus hyperantus

The first five on June 29th increased to a best ever 189 on July 11th and the last two were seen on

August 10th.


46

BUTTERFLIES – YEAR BY YEAR REVIEW

Year 13 12 11 10 09 08 07 06 05 04 03 Last seen

Small Skipper l l l l l l l l l l l

Essex Skipper l l

Large Skipper l l l l l l l l l l l

Clouded Yellow l l l l l l

Brimstone l l l l l l l l l l l

Large White l l l l l l l l l l l

Small White l l l l l l l l l l l

Green-veined White l l l l l l l l l l l

Orange Tip l l l l l l l l l l l

Purple Hairstreak l l l l l l l l l l l

White-letter Hairstreak l l l l l l l l l l l

Small Copper l l l l l l l l l l l

Brown Argus l l l l l l l l l l l

Common Blue l l l l l l l l l l l

Chalkhill Blue l

Holly Blue l l l l l l l l l l l

Purple Emperor l

Red Admiral l l l l l l l l l l l

Painted Lady l l l l l l l l l l

Small Tortoiseshell l l l l l l l l l l l

Peacock l l l l l l l l l l l

Comma l l l l l l l l l l l

Dark Green Fritillary l

Silver-washed Fritillary l

Speckled Wood l l l l l l l l l l l

Wall Brown 1993

Marbled White l l l l l l l l l l l

Gatekeeper l l l l l l l l l l l

Meadow Brown l l l l l l l l l l l

Small Heath l l l

Ringlet l l l l l l l l

Key: l = recorded in that year

Stephen Murray


47

THE DRAGONFLIES OF HILFIELD PARK RESERVOIR 2013

BANDED DEMOISELLE Calopteryx splendens

A pretty good year for this riverine species, seen on five dates between July 6th and August 21st.

The sole multiple sighting was of two males on July 13th.

RED-EYED DAMSELFLY Erythromma najas

A disappointing year with mainly one-three seen between June 19th and August 30th , with the

exception of nine males on July 5th. No breeding behaviour was observed.

SMALL RED-EYED DAMSELFLY Erythromma viridulum

This distinctive but easily overlooked species returned to having another poor year. Recorded

between August 6th and the 27th the best count was of four males on the latter date. The only

ovipositing pair was seen on August 8th.

AZURE DAMSELFLY Coenagrion puella

The only record concerned a single male at one of the south bank ponds on June 14th.

COMMON BLUE DAMSELFLY Enallagma cyathigerum

An extremely abundant species of the reservoir recorded between May 25th and October 8th.

BLUE-TAILED DAMSELFLY Ischnura elegans

Seen between June 14th and August 26th with a best count of four on July 8th.

MIGRANT HAWKER Aeshna mixta

The first two were seen on August 17th, and throughout September over 50 were spread around

the reservoir on several dates. This marked a welcome return to form after the inexplicable dip in

numbers in the previous year. Three on October 24th appeared to be the last record of the year,

until one made an unexpected appearance on November 13th.


48

SOUTHERN HAWKER Aeshna cyanea

A fairly good year with records on eight dates between August 4th and September 24th. The only

multiple sightings were of a separate male and female on August 10th and 11th.

BROWN HAWKER Aeshna grandis

This species was seen on just eight dates between July 15th and September 2nd. The best count

was of only four on July 18th and two ovipositing females seen on the 26th.

VAGRANT EMPEROR Anax ephippiger

By far the biggest event of the dragonfly year was the discovery of a male behind the south-east

bay on October 6th. It gave prolonged close range views as it hung from dead thistle stems but

unfortunately flew off shortly before the arrival of a photographer. A search failed to relocate it, as

did more extensive searches on the following days.

This record has been accepted by the national dragonfly rarities committee and represents

the first record for Hilfield and Hertfordshire.

EMPEROR DRAGONFLY Anax imperator

After a late first sighting on June 25th numbers rose to very impressive levels, peaking at 11 males

and two ovipositing females on July 15th. Breeding activity was also better than in recent years

with ovipositing females seen on a further eight dates. The final record was of one male on August

18th.

BROAD-BODIED CHASER Libellula depressa

Two of the three south bank ponds were enlarged during the previous autumn, resulting in a much

improved set of records. Single males were noted on thirteen dates between June 19th and July

28th, plus two males on July 6th, and single ovipositing females were observed on five dates.

BLACK-TAILED SKIMMER Orthetrum cancellatum

Recorded between June 19th and August 27th but a best count of 36 on July 17th was only one-

third that of the previous year.

COMMON DARTER Sympetrum striolatum

Following the first three on August 11th there were frequent records until the last sighting of two

on November 10th. Numbers appeared higher than usual, with a best count of 20 males and four

ovipositing pairs on September 20th.

RUDDY DARTER Sympetrum sanguineum

Sightings on four dates between August 18th and 30th was better than average, but fell well short

of the excellent numbers of the previous year. All were males and the only multiple count was of

two at the south bank ponds on the 29th.


49

RED-VEINED DARTER Sympetrum fonscolombii

Three males were in hunting flight along the dam on July 5th, four on the 6th, and at a brief

glance one on the 7th. Often they were fifty yards or more out over the water and could easily be

overlooked. Despite prolonged watching no females were seen to arrive.

DRAGONFLIES – YEAR BY YEAR REVIEW

Year 13 12 11 10 09 08 07 06 05 04 03 Last seen

Banded Demoiselle l l l l l l l l l l

Emerald Damselfly 2000

Large Red Damselfly l l l l l l l l l l

Red-eyed Damselfly l l l l l l l l l l l

Small Red-eyed Damselfly l l l l l l l l l

Azure Damselfly l l l l l l l l

Common Blue Damselfly l l l l l l l l l l l

Blue-tailed Damselfly l l l l l l l l l l l

Migrant Hawker l l l l l l l l l l l

Southern Hawker l l l l l l l l l l l

Brown Hawker l l l l l l l l l l l

Vagrant Emperor l

Emperor Dragonfly l l l l l l l l l l l

Lesser Emperor l l l l l

Hairy Dragonfly l

Four-spotted Chaser l l l l l

Broad-bodied Chaser l l l l l l l l l l l

Black-tailed Skimmer l l l l l l l l l l l

Common Darter l l l l l l l l l l l

Ruddy Darter l l l l l

Yellow-winged Darter 1995

Red-veined Darter l l l l l l

Key: l = recorded in that year.

Stephen Murray


50

MAMMAL, REPTILE, AMPHIBIAN AND FISH RECORDS 2013

MAMMALS

COMMON SHREW Sorex araneus

One record on 23 June.

COMMON MOLE Talpa europaea

Mole hills were noted throughout the year.

GREY SQUIRREL Sciurus carolinensis

Local resident.

BROWN RAT Rattus norvegicus

Two records this year both involving dead rats, the first was found on the south bank on 12 January

and the second on the north bank on 14 April.

RABBIT Oryctolagus cuniculus

Local resident, with a maximum count of two on 24 March.

RED FOX Vulpes vulpes

Nineteen records this year all of singletons.

WEASEL Mustela nivalis

Three records all around the garage area, starting with one on 10 March, two on 14 October and

finally with one on 1 November.

MUNTJAC Muntiacus reevesi

There were 21 records in 2013 with a maximum count of seven on 30 March. Regular sightings of

five were seen throughout February.


51

REPTILES AND AMPHIBIANS

GRASS SNAKE Natrix natrix

Four records, all involving singletons which were dispersed around the reserve, on the following

dates: 14 April, 6 June, 2 and 12 September.

TERRAPIN SPECIES

The Terrapin which had been on the reserve for several years was caught and removed from site.

NEWT sp

Three records this year, all coming from the south bank. Two from the new ponds adjacent to the

water’s edge and one from the mini ponds by the upper path, with a maximum count of three on

23 April, two from the lower ponds and one from the mini ponds. A single newt was recorded on

16 May as well.

FISH

MIRROR CARP Cyprinus carpio

Two sightings, the first on 2 June off the north bank with an estimated weight of 8lbs. The second

sighting was of two estimated to weigh in at 7lbs and 8lbs.

Bob Cripps


52

Code Taxon Vernacular Individuals Date Status Local status

17 Hepialus lupulinus Common Swift 23 21-Jun-13 Common

25 Ectoedemia intimella 1 15-Jul-13 Local New to Hilfield

37 Ectoedemia albifasciella 1 21-Jun-13 Common New to Hilfield

99 Stigmella hybnerella 4 15-Jul-13 Common New to Hilfield

123 Tischeria ekebladella 1 21-Jun-13 Common

227 Monopis laevigella Skin Moth 2 21-Jun-13 Common

308 Parornix finitimella 1 15-Jul-13 Common

309 Deltaornix torquillella 1 15-Jul-13 Common New to Hilfield

333 Phyllonorycter salictella

viminiella

1 15-Jul-13 Common

410 Argyresthia brockeella 1 15-Jul-13 Common New to Hilfield

411 Argyresthia goedartella 2 15-Jul-13 Common

417 Argyresthia spinosella 2 21-Jun-13 Common New to Hilfield

424 Yponomeuta evonymella Bird-cherry Ermine 34 15-Jul-13 Common

428 Yponomeuta rorrella Willow Ermine 2 15-Jul-13 Local New to Hilfield

441 Paraswammerdamia

nebulella

18 15-Jul-13 Common New to Hilfield

450 Scythropia crataegella Hawthorn Moth 2 15-Jul-13 Common

464 Plutella xylostella Diamond-back Moth 3 21-Jun-13 Migrant

481 Epermenia falciformis 1 21-Jun-13 Local New to Hilfield

492 Coleophora flavipennella 1 15-Jul-13 Common

493 Coleophora serratella 1 15-Jul-13 Common

504 Coleophora

lusciniaepennella


535 Coleophora ibipennella 2 15-Jul-13 Local

537 Coleophora kuehnella 2 15-Jul-13 Local New to Hilfield

553 Coleophora striatipennella 1 21-Jun-13 Common

559 Coleophora peribenanderi 1 21-Jun-13 Common

582 Coleophora

glaucicolella


584 Coleophora alticolella 1 21-Jun-13 Common New to Hilfield

606 Elachista humilis 1 21-Jun-13 Common

640 Batia lunaris 1 15-Jul-13 Common New to Hilfield

642 Batia unitella 4 15-Jul-13 Common

658 Carcina quercana 2 15-Jul-13 Common

668 Luquetia lobella 1 21-Jun-13 Local New to Hilfield

756 Parachronistis albiceps 1 15-Jul-13 Local New to Hilfield

757 Recurvaria nanella 1 15-Jul-13 Nb New to Hilfield

787 Bryotropha terrella 3 15-Jul-13 Common

4 21-Jun-13

844 Syncopacma larseniella 18 15-Jul-13 Local New to Hilfield

874 Blastobasis lacticolella 1 15-Jul-13 Common

SPECIES LIST FOR HILFIELD RESERVOIR IN 2013

MOTH (LEPIDOPTERA) RECORDING AT HILFIELD PARK RESERVOIR 2013


53


906 Blastodacna atra Apple Pith Moth 1 15-Jul-13 Nb New to Hilfield

937 Agapeta hamana 4 21-Jun-13 Common

12 15-Jul-13

0964a Cochylis molliculana 1 15-Jul-13 Local New to Hilfield

965 Cochylis hybridella 2 15-Jul-13 Local

970 Pandemis cerasana Barred Fruit-tree Tortrix 1 21-Jun-13 Common

4 15-Jul-13

972 Pandemis heparana Dark Fruit-tree Tortrix 2 15-Jul-13 Common

977 Archips podana Large Fruit-tree Tortrix 6 15-Jul-13 Common

979 Archips crataegana 1 15-Jul-13 Local New to Hilfield

980 Archips xylosteana Variegated Golden Tortrix 8 15-Jul-13 Common

983 Choristoneura

hebenstreitella

4 21-Jun-13 Local New to Hilfield

989 Aphelia paleana Timothy Tortrix 1 15-Jul-13 Common

993 Clepsis spectrana Cyclamen Tortrix 1 15-Jul-13 Common

998 Epiphyas postvittana Light Brown Apple Moth 2 15-Jul-13 Common

1001 Lozotaeniodes formosanus 2 15-Jul-13 Common

1002 Lozotaenia forsterana 1 15-Jul-13 Common

1011 Pseudargyrotoza

conwagana

2 21-Jun-13 Common New to Hilfield

2 15-Jul-13

1018 Cnephasia communana 2 15-Jul-13 Local

7 21-Jun-13

1020 Cnephasia stephensiana Grey Tortrix 9 15-Jul-13 Common

1021 Cnephasia asseclana Flax Tortrix 7 15-Jul-13 Common New to Hilfield

1024 Cnephasia incertana Light Grey Tortrix 1 15-Jul-13 Common

1032 Aleimma loeflingiana 22 15-Jul-13 Common

1033 Tortrix viridana Green Oak Tortrix 16 15-Jul-13 Common

1044 Acleris ferrugana 3 15-Jul-13 Common

1053 Acleris hastiana 1 15-Jul-13 Common New to Hilfield

1063 Celypha striana 1 15-Jul-13 Common New to Hilfield

1076 Celypha lacunana 11 15-Jul-13 Common

6 21-Jun-13

1079 Piniphila bifasciana 1 15-Jul-13 Local New to Hilfield

1082 Hedya pruniana Plum Tortrix 4 15-Jul-13 Common

3 21-Jun-13

1083 Hedya nubiferana Marbled Orchard Tortrix 15 15-Jul-13 Common

1084 Hedya ochroleucana 1 15-Jul-13 Common New to Hilfield

1086 Hedya salicella 14 15-Jul-13 Common

1108 Lobesia abscisana 4 15-Jul-13 Common

1113 Eudemis profundana 1 15-Jul-13 Common

1115 Ancylis achatana 6 15-Jul-13 Common

1146 Epinotia rubiginosana 1 15-Jul-13 Local New to Hilfield

1165 Zeiraphera isertana 15 15-Jul-13 Common

1168 Gypsonoma sociana 2 15-Jul-13 Common New to Hilfield

1169 Gypsonoma dealbana 4 15-Jul-13 Common

1175 Epiblema uddmanniana Bramble Shoot Moth 1 21-Jun-13 Common


54


3 15-Jul-13

1176 Epiblema trimaculana 2 21-Jun-13 Common

1177 Epiblema rosaecolana 4 21-Jun-13 Common New to Hilfield

1187 Epiblema costipunctana 1 15-Jul-13 Common New to Hilfield

1197 Eucosma campoliliana 2 15-Jul-13 Common

1200 Eucosma hohenwartiana 25 15-Jul-13 Common

1201 Eucosma cana 2 21-Jun-13 Common

5 15-Jul-13

1205 Spilonota ocellana Bud Moth 3 15-Jul-13 Common

1236 Pammene fasciana 2 15-Jul-13 Common New to Hilfield

1293 Chrysoteuchia culmella Garden Grass-veneer 37 15-Jul-13 Common

4 21-Jun-13

1301 Crambus lathoniellus 5 21-Jun-13 Common

1 15-Jul-13

1304 Agriphila straminella 3 15-Jul-13 Common

1316 Catoptria falsella 10 15-Jul-13 Common

1331 Acentria ephemerella Water Veneer 6 15-Jul-13 Common

1333 Scoparia pyralella 4 21-Jun-13 Common

2 15-Jul-13

1334 Scoparia ambigualis 2 15-Jul-13 Common

12 21-Jun-13

1336 Eudonia pallida 2 15-Jul-13 Local New to Hilfield

1338 Dipleurina lacustrata 8 15-Jul-13 Common

1378 Phlyctaenia coronata 1 15-Jul-13 Common New to Hilfield

1390 Udea prunalis 1 15-Jul-13 Common

1392 Udea olivalis 1 21-Jun-13 Common

2 15-Jul-13

1415 Orthopygia glaucinalis 1 15-Jul-13 Common New to Hilfield

1426 Achroia grisella Lesser Wax Moth 1 15-Jul-13 Local New to Hilfield

1428 Aphomia sociella Bee Moth 1 21-Jun-13 Common

1 15-Jul-13

1436 Conobathra repandana 2 15-Jul-13 Common

1437 Acrobasis consociella 2 15-Jul-13 Common

1439 Trachycera advenella 3 15-Jul-13 Common

1452 Phycita roborella 26 15-Jul-13 Common

1455 Dioryctria simplicella 1 15-Jul-13 Local New to Hilfield

1461 Assara terebrella 1 15-Jul-13 Na New to Hilfield

1474 Ephestia parasitella

unicolorella

3 15-Jul-13 Local

1483 Phycitodes binaevella 1 15-Jul-13 Common

1504 Platyptilia pallidactyla 6 15-Jul-13 Common

1648 Drepana falcataria Pebble Hook-tip 1 21-Jun-13 Common

1652 Thyatira batis Peach Blossom 1 21-Jun-13 Common

14 15-Jul-13

1653 Habrosyne pyritoides Buff Arches 1 21-Jun-13 Common

42 15-Jul-13

1669 Hemithea aestivaria Common Emerald 6 15-Jul-13 Common


55


1702 Idaea biselata Small Fan-footed Wave 9 15-Jul-13 Common

1705 Idaea fuscovenosa Dwarf Cream Wave 1 15-Jul-13 Local New to Hilfield

1708 Idaea dimidiata Single-dotted Wave 1 15-Jul-13 Common

1711 Idaea trigeminata Treble Brown Spot 1 15-Jul-13 Local New to Hilfield

1713 Idaea aversata Riband Wave 15 15-Jul-13 Common

1727 Xanthorhoe montanata Silver-ground Carpet 3 21-Jun-13 Common

1738 Epirrhoe alternata Common Carpet 2 21-Jun-13 Common

1742 Camptogramma bilineata

bilineata

Yellow Shell 1 15-Jul-13 Common

1758 Eulithis pyraliata Barred Straw 2 15-Jul-13 Common

1764 Chloroclysta truncata Common Marbled

Carpet

1 21-Jun-13 Common

2 15-Jul-13

1765 Cidaria fulvata Barred Yellow 3 15-Jul-13 Common

1766 Plemyria rubiginata

rubiginata

Blue-bordered Carpet 4 15-Jul-13 Common New to Hilfield

1768 Thera obeliscata Grey Pine Carpet 18 15-Jul-13 Common

1776 Colostygia pectinataria Green Carpet 4 21-Jun-13 Common

1773 Electrophaes corylata Broken-barred Carpet 3 21-Jun-13 Common

1777 Hydriomena furcata July Highflyer 9 15-Jul-13 Common

1778 Hydriomena impluviata May Highflyer 1 21-Jun-13 Common

1803 Perizoma alchemillata Small Rivulet 1 15-Jul-13 Common

1811 Eupithecia tenuiata Slender Pug 4 15-Jul-13 Common

1837 Eupithecia subfuscata Grey Pug 6 21-Jun-13 Common

6 15-Jul-13

1860 Pasiphila rectangulata Green Pug 8 15-Jul-13 Common

1862 Gymnoscelis rufifasciata Double-striped Pug 2 15-Jul-13 Common

1887 Lomaspilis marginata Clouded Border 2 15-Jul-13 Common

1893 Macaria liturata Tawny-barred Angle 1 21-Jun-13 Common

5 15-Jul-13

1904 Plagodis dolabraria Scorched Wing 1 21-Jun-13 Common

1906 Opisthograptis luteolata Brimstone Moth 45 15-Jul-13 Common

1921 Crocallis elinguaria Scalloped Oak 1 15-Jul-13 Common

1922 Ourapteryx sambucaria Swallow-tailed Moth 8 15-Jul-13 Common New to Hilfield

1931 Biston betularia Peppered Moth 1 21-Jun-13 Common

5 15-Jul-13

1937 Peribatodes rhomboidaria Willow Beauty 1 21-Jun-13 Common

1937 Peribatodes rhomboidaria Willow Beauty 5 15-Jul-13 Common

1941 Alcis repandata Mottled Beauty 13 15-Jul-13 Common

1944 Hypomecis punctinalis Pale Oak Beauty 1 21-Jun-13 Common New to Hilfield

1950 Parectropis similaria Brindled White-spot 1 21-Jun-13 Local New to Hilfield

1954 Bupalus piniaria Bordered White 8 15-Jul-13 Common New to Hilfield

1955 Cabera pusaria Common White Wave 1 21-Jun-13 Common

13 15-Jul-13

1956 Cabera exanthemata Common Wave 3 15-Jul-13 Common

1958 Lomographa temerata Clouded Silver 12 15-Jul-13 Common

62 21-Jun-13


56


1961 Campaea margaritata Light Emerald 5 15-Jul-13 Common

12 21-Jun-13

1962 Hylaea fasciaria Barred Red 1 15-Jul-13 Common

1981 Laothoe populi Poplar Hawk-moth 1 15-Jul-13 Common

1991 Deilephila elpenor Elephant Hawk-moth 13 15-Jul-13 Common

1994 Phalera bucephala Buff-tip 1 15-Jul-13 Common

2011 Pterostoma palpina Pale Prominent 5 21-Jun-13 Common

2026 Orgyia antiqua Vapourer 1 15-Jul-13 Common

2031 Leucoma salicis White Satin 1 15-Jul-13 Local New to Hilfield

2039 Atolmis rubricollis Red-necked Footman 1 15-Jul-13 Local New to Hilfield

2043 Eilema sororcula Orange Footman 2 21-Jun-13 Local

2047 Eilema complana Scarce Footman 18 15-Jul-13 Local

2049 Eilema depressa Buff Footman 7 15-Jul-13 Local

2050 Eilema lurideola Common Footman 7 15-Jul-13 Common

2060 Spilosoma lubricipeda White Ermine 1 21-Jun-13 Common

2064 Phragmatobia fuliginosa Ruby Tiger 1 15-Jul-13 Common

2069 Tyria jacobaeae Cinnabar 2 21-Jun-13 Common

2077 Nola cucullatella Short-cloaked Moth 6 15-Jul-13 Common

2088 Agrotis clavis Heart and Club 3 15-Jul-13 Common

2089 Agrotis exclamationis Heart and Dart 3 21-Jun-13 Common

13 15-Jul-13

2098 Axylia putris Flame 8 15-Jul-13 Common

2102 Ochropleura plecta Flame Shoulder 4 21-Jun-13 Common

5 15-Jul-13

2107 Noctua pronuba Large Yellow Underwing 2 15-Jul-13 Common

2110 Noctua fimbriata Broad-bordered Yellow

Underwing

1 15-Jul-13 Common

2123 Diarsia rubi Small Square-spot 3 21-Jun-13 Common

2126 Xestia c-nigrum Setaceous Hebrew

Character

1 15-Jul-13 Common

2128 Xestia triangulum Double Square-spot 11 15-Jul-13 Common

2147 Hada plebeja Shears 1 21-Jun-13 Common

2150 Polia nebulosa Grey Arches 1 15-Jul-13 Common New to Hilfield

2157 Lacanobia w-latinum Light Brocade 1 21-Jun-13 Local New to Hilfield

2160 Lacanobia oleracea Bright-line Brown-eye 1 15-Jul-13 Common

2164 Hecatera bicolorata Broad-barred White 1 15-Jul-13 Common New to Hilfield

2193 Mythimna ferrago Clay 5 15-Jul-13 Common

2198 Mythimna impura impura Smoky Wainscot 3 15-Jul-13 Common

2205 Mythimna comma Shoulder-striped

Wainscot

1 21-Jun-13 Common

2 15-Jul-13

2278 Acronicta megacephala Poplar Grey 5 15-Jul-13 Common

2280 Acronicta leporina Miller 2 15-Jul-13 Common New to Hilfield

2283 Acronicta tridens Dark Dagger 1 15-Jul-13 Common New to Hilfield

2284 Acronicta psi Grey Dagger 1 21-Jun-13 Common New to Hilfield

6 15-Jul-13

2289 Acronicta rumicis Knot Grass 7 15-Jul-13 Common


57


2318 Cosmia trapezina Dun-bar 5 15-Jul-13 Common

2319 Cosmia pyralina Lunar-spotted Pinion 3 15-Jul-13 Local

2321 Apamea monoglypha Dark Arches 27 15-Jul-13 Common

2322 Apamea lithoxylaea Light Arches 1 21-Jun-13 Common

8 15-Jul-13

2334 Apamea sordens Rustic Shoulder-knot 1 21-Jun-13 Common

1 15-Jul-13

2337 Oligia strigilis Marbled Minor 6 21-Jun-13 Common

8 15-Jul-13

2339 Oligia latruncula Tawny Marbled Minor 2 21-Jun-13 Common

10 15-Jul-13

2340 Oligia fasciuncula Middle-barred Minor 27 21-Jun-13 Common

2341 Mesoligia furuncula Cloaked Minor 1 15-Jul-13 Common

2343 Mesapamea secalis Common Rustic 1 15-Jul-13 Common

2345 Photedes minima Small Dotted Buff 1 15-Jul-13 Common

2380 Charanyca trigrammica Treble Lines 1 21-Jun-13 Common

2381 Hoplodrina alsines Uncertain 7 15-Jul-13 Common

2382 Hoplodrina blanda Rustic 1 15-Jul-13 Common

2387 Caradrina morpheus Mottled Rustic 1 15-Jul-13 Common

2410 Protodeltote pygarga Marbled White Spot 32 21-Jun-13 Common

28 15-Jul-13

2421 Bena bicolorana Scarce Silver-lines 2 15-Jul-13 Local New to Hilfield

2422 Pseudoips prasinana Green Silver-lines 1 21-Jun-13 Common New to Hilfield

1 15-Jul-13

2423 Nycteola revayana Oak Nycteoline 4 15-Jul-13 Common

2434 Diachrysia chrysitis Burnished Brass 5 15-Jul-13 Common

2441 Autographa gamma Silver Y 3 15-Jul-13 Common

2442 Autographa pulchrina Beautiful Golden Y 3 15-Jul-13 Common New to Hilfield

2450 Abrostola tripartita Spectacle 1 21-Jun-13 Common

2473 Laspeyria flexula Beautiful Hook-tip 14 15-Jul-13 Common New to Hilfield

2474 Rivula sericealis Straw Dot 18 21-Jun-13 Common

1 15-Jul-13

2477 Hypena proboscidalis Snout 4 21-Jun-13 Common

10 15-Jul-13

2492 Herminia grisealis Small Fan-foot 2 21-Jun-13 Common

2493 Macrochilo cribrumalis Dotted Fan-foot 2 15-Jul-13 Nb New to Hilfield

Rachel Terry


58

THE ULTRAVIOLET REFLECTANCE OF FEATHERS

November 2013

Richard Melzack Ph.D

This study was carried out primarily at Hilfield Park Reservoir with the help of the bird ringing

group, who afforded me the chance to get close to many bird species, and who taught me a great

deal about the birds, for which I will always be grateful.

Thank you Peter, Jack, Mike, Bob, Eirwen and Kenny.

Introduction

When it was first discovered that birds had the ability to see within the ultraviolet (UV) there was

great excitement in avian research to find the ‘hidden from human view’ signals that this ability

could have.

Was there an ability to use UV sight in the attraction of a mate? Did this ability give them a way of

locating food without the need for colour vision? Did it help in flight orientation?

It was a new line of study that was worked on with gusto. Claims have been made for a number of

species having specific UV abilities. There is a good summary given by Cuthill, I.C. et al. 1999. ‘UV

vision and its functions in birds’ In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr.,

Durban: 2743-2758. Johannesburg: BirdLife South Africa, and an updated report by Stephens and

Cuthill entitled: ‘Hidden Messages: Are Ultraviolet Signals a Signals a Special Channel in Avian

Communication?’ Bioscience 57(6): 501-507. 2007.

To summarise, UV and/or near violet sight has been reported in a number of bird species. To

date about 40 species across a range of taxa have been studied either by behavioural studies,

spectrophotometric or genetic studies for UV abilities. Although this is a small sample of all bird

species (there are around 10,000 bird species globally) it is assumed, and I suggest, probable, that

this ability is common in birds to a larger or lesser extent.

There are some well reported studies suggesting practical uses of UV vision, one being the female

Blue Tit’s Cyanistes caeruleus ability to select a mate, with the catchy title: ‘Blue Tits are ultraviolet

tits’ published in the Proceedings of the Royal Society on 22nd March 1998 in Vol: 265; number

1395; pp 451-455 Lond B, and another popular paper suggesting that the Common Kestrel Falco

tinnunculus can track their prey (voles) using the UV reflectance of the excretion trails. This paper,

entitled: ‘Attraction of Kestrels to vole scent marks visible in ultraviolet light’, was accepted and

published by the highly prestigious journal Nature Vol 373 1995.

I should make my position clear, after reading these two papers, I consider both the Blue Tit

and Kestrel conclusions unproven as they, first, have not been replicated, and second, they are

behavioural studies. Behavioural studies are of concern as there will always be, to a lesser or greater


59

extent, an element of subjectivity within the data set. However, it is clear that, due to the reporting

of these two conclusions in the popular press, the results have been ‘accepted’ as biological fact.

Indeed, my suspicions were heightened, regarding the Kestrel paper, when I decided to take some

UV images of rodents (these were white mice) in a cage full of litter that they had been running

about on all night. I expected an image which reflected the litter in the UV, and found none.

Due to my concerns I made contact with one of the main researchers in the field of avian senses,

Prof Graham Martin, Emeritus Professor of Avian Sensory Science at Birmingham University, and

asked him for his opinion about these studies, he remarked:

Re: The Blue Tit study. That he agreed that it (the study) needs to be replicated, and continued by

adding, that ‘the trouble is that these days no one wants to just replicate a study and confirm a

finding since it would not get published in a “high impact” journal and everyone now chases high

impact publications, so whether it will be replicated is an open question. Nowadays it seems that

if a result is published in a reputable journal then that is sufficient to say that it must be true.’ My

point exactly!

Re: The Kestrel study: he suggested that the study had always been a little contentious, adding,

perhaps a little too neat? He then mentioned that there has been a recent paper which challenges

the conclusion that urine trails could provide a cue adding ‘it does seem that the rather neat story

about Kestrels using vole urine trails as a means of locating a good foraging site, may be suspect.’

Another study, however, based on UV imaging, suggests that there are bird species that have a so

called ‘secret signal’ that only birds can see, in a book by Prof Geoffrey E Hill called Bird Colouration

published by National Geographic. UV images of the birds seem to show a different pattern in

the feathers that is revealed in the colour spectral range. This genus is Myophonus, the whistling

thrush. That, however, is the only reported genus, so far, using a UV camera, that may have a UV

pattern. What it is used for is still a mystery, if indeed it is confirmed. This genus is worthy of more

study in this area.

This, as other studies on UV feather reflectance, have tended to be carried out on skins of birds

from museum specimens. A case in point can be found in a paper by Eaton and Lanyon called: The

ubiquity of avian ultraviolet plumage reflectance in Proceedings of Biological Science 2003 Vol. 270

pp. 1721-1726. This study collects UV reflectance data on the dorsal and ventral patches of 312

bird species representing 142 families. They found that all specimens reflected some UV light, and

concluded that all avian studies on behaviour, ecology, and evolution involving plumage colouration

would benefit by taking UV reflectance into account.

What is clear is that there are no UV reflectance images of live birds in the literature. In a personal

communication with Prof Innes Cuthill, Professor of Behavioural and Sensory Ecology, Bristol

University, he pointed out the pitfalls in the collection of these images to get hard core scientific

data, and he is of course, correct, but nevertheless, there is merit in taking pictures of live birds to

see, as he put it, ‘what is out there’.

This was the purpose of the Hilfield study.


60

Background

What is sight?

There have been some significant advances in the field of vision in recent years, in the biochemical,

and genomic (genetic) fields, where some of the gene sequences that are responsible for sight have

been identified.

In summary, sight is the brain’s interpretation of electromagnetic waves first arriving at receptors

in the back of the eye (the cone and rod cells of the retina), where opsins (also known as visual

pigments) are the first step of the biochemical cascade which ends at the sight centre of the brain,

called the visual cortex, this is the site which interprets this cascade as sight. Colour vision occurs

by the selective agitation of the cones, by different wavelengths. The, so called, visible spectrum,

commonly understood to be between 400nm (nm=nanometer, the wavelength measure), and

700nm, is the range Homo sapiens (humans) can detect. Within that range there are three main

peaks of cone sensitivity located in the retina at the back of the eye, namely red wavelength

(570nm), green (540nm), and blue (450nm). This kind of colour vision is called trichromatic as it has

three peak sensitivities. From these primary visual colours, and their ‘mixing’, a pallet of colours are

perceived in the visual cortex.

Birds and other animals, including reptiles and some fish are tetrachromatic. Meaning that they

have three peaks in the ‘visible’ spectrum just as humans do, but that they also have another cone

that has a peak sensitivity between 300nm and 400nm. This area of the electromagnetic spectrum

is described as ultra violet light.

Vision in birds

It is understood that birds not only have the additional UV sensitivity but that they have much

better colour vision than humans.

Within 400nm to 700nm (the colour vision wavelengths), birds have improved vision due to the

presence of coloured oil droplets within the cones cells. The effect of this is to alter the wavelength

and so expand the range of colour and hues they can see. This is beyond human perceptual

abilities.

It is fair to say, therefore, that birds have a much wider visual range than humans, seeing many

more colour hues than we can see and additionally being able to see in the UV.

Furthermore, when comparing to human eyes other differences can be seen.

Bird’s eyes have striated iris muscle groups. This gives them the ability to open and close their irises

voluntarily (personal communication, Dr David Williams, Cambridge University), whereas our irises

have smooth muscle groups which open and close involuntarily in response to light intensity. The

effect being that they can control the aperture, we cannot. It has been suggested that some birds

use this ability as a signalling device (Craig and Hulley 2004 South African Journal of Science 100,

November/December 2004).


61

Also, birds have a so called ‘third eye lid’, the nictitating membrane, which is transparent or

translucent, the function of which is to protect and moisten the eye while maintaining visibility.

Further, it has been suggested that bird’s eyes are large in proportion to their skull size and

as such do not have the ability to swivel their eyes as mammals do as they don’t have the

musculature to do so. Subsequently their eyes are fixed. This is not quite the case. Birds do have eye

musculature that can rotate the eye between twelve and fifteen degrees in any direction (personal

communication, Prof. Graham Martin). This is much less than in mammals, including humans,

however, it should be stated that, contrary to much of the literature, they have some ability to

move their eyes. There is a paper in Ibis 2008 150: pp. 485-494: Fig 4, by Prof Martin et al, with

images showing the eye movements of cormorants, which makes this point very well.

Anatomy of bird retinas

The retinal architecture in birds has been studied by a ophthalmologist called Casey Albert Wood.

He published a book of hand drawn pictures of a large array of bird species in 1917. This book

is still referred to today, and can be viewed on the internet (search for the Fundus Oculi of birds

by Casey A Wood). In it he shows that a number of birds of prey have two fovea (the fovea is the

part of the retina that shows up as a pit in the retina, and is responsible for the sharpest vision)

one is shallow (for close vision) and one is deep (for distance vision), indeed a paper has recently

been published suggesting a mathematical model of the way a peregrine falcon could keep it’s

prey aligned with it’s deep fovea having a spiral flight into it’s prey, and keeping the deep fovea in

position until the last moment. (The Deep Fovea, sideways vision and spiral flight paths in Raptors

Nov 2000, Vance A. Tucker, The Journal of Experimental Biology 203, 3745-3754). Mind you I have

never seen a peregrine dive the way they describe!

Feather colours

When looking at the colours of the feathers in the visual range 400nm to 700nm, it has been

determined that the colours seen are based on a mixture of pigments, and structural colours.

The darker colours are primarily produced by a family of pigments called melanins, such as black,

brown, and red. These are produced by biochemical production of the cells in the feather stem

cells. The lighter colours such as yellow are metabolised from carotenes ingested in food and then

metabolised, and the other colouration is based on the nanostructure of the feathers, these are the

structural colours mentioned above, indeed all blue colours in birds is derived this way.

Iridescence is also a nanostructural phenomenon, and is perceived when light strikes the

nanostructure of the feathers and reflects different wavelengths selectively when the bird moves.

The result being that at any one time the wave length, and so the colour, reflected will be different

producing the iridescence perceived.

The mixing and dosage of this array of colours by pigments and structural colours produces a pallet

(gamut) of colours unsurpassed in the animal kingdom.

There are other rarer feather pigments such as psittacofulvins and psittacins which produce reds,

yellows and greens in parrots. Porphyrins, is another pigment group, which are produced by


62

modifying amino acids, and are found in some owls, pigeons and gallinaceous species. See www.

birds.cornell.edu/AllAboutBirds/studying/feathers/color. 1

And then there Is white

A white feather is understood to be a feather without pigment, and that the white perceived is the

reflection of all wavelengths (full spectrum) via the nanostructural makeup of the white feather.

This logically suggests that there are structural differences to the structure of a white feather and

a blue feather, as both colours are structural. To date I have not found any studies confirming this

suggestion.

Method

The birds were captured during general mist netting sessions. Ultra violet images were taken of

the birds caught using a converted Nikon D300 camera sensitive to 300nm to 400nm. Due to the

movement of the birds in the hand and the speed needed for exposure, direct daylight would not

give clear results with this system, so a UV flash gun was employed. The effect was to give a clear

picture of the bird on a dark background.

Robin Erithacus rubecula. Robin Erithacus rubecula.

Caught Hilfield 10th April 2011. Caught Hilfield 24th April 2011.

1 Note: There is a recent paper entitled: ‘Structure and optical function of amorphous photonic nanostructures

from avian feather barbs: a comparative small angle X-ray scattering (SAXS) analysis of 230 bird species’ by

Vinod et al in Journal of the Royal Society 2012 suggesting that the nanostructure of non iridescent barbs

within the feather that produce the colours are likely to be self assembled having evolved over millions of years

of selection resulting in a consistent optical function.


63

Great Spotted Woodpecker Dendrocopos

major. Wing, caught Hilfield 1st April 2012.

Kingfisher Alcedo atthis. Caught Hilfield

28/8/2011.


28/8/2011.

Great Spotted Woodpecker Dendrocopos

major. Caught Hilfield.

Mistle Thrush Turdus viscivorus. Caught Hilfield

22nd April 2012 Ring LA35851.


28/8/2011.


64

Male Chaffinch Fringilla coelebs.

Goldfinch Carduelis carduelis. Caught Hilfield

24th July 2011.

Jay Garrulus glandarius. Caught Hilfield 22nd

July 2012.

Male Chaffinch Fringilla coelebs. Caught Hilfield

13th March 2011.

Goldfinch Carduelis carduelis. Caught Hilfield

24th July 2011.

Jay Garrulus glandarius. Caught Hilfield 10th

April 2010.


65

Long-tailed Tit Aegithalos caudatus. Caught

Hilfield 4th September 2011.

Male Bullfinch Pyrrhula pyrrhula. Caught 19th

February 2012.

Blue Tit Cyanistes caeruleus. Caught Hilfield 1st

April 2012.

Long-tailed Tit Aegithalos caudatus. Caught

Hilfield 24th July 2011.

Male Bullfinch Pyrrhula pyrrhula. Caught Hilfield

29th May 2011.

Blue Tit Cyanistes caeruleus. Caught Hilfield

13th March 2011.


66

Results

The result was a set of black and white pictures, from Hilfield, to see if there was any hidden UV

signals in live specimens of birds captured.

As can be seen from a selection of images set out here above, that there are no hidden signals

in the UV in the species photographed. Further, the images show that lighter and darker areas of

birds mimic the visible spectrum pattern. Indeed, it seems from this study that there may be a clear

distinction between the different colours based on the dominant colour.

It suggests that when melanins are dominant the main effect in UV absorption as in the dark effect

in the Robin’s Erithacus rubecula breast, and when the carotenes are dominant then the main effect

is UV reflection, as in the wing of the Goldfinch Carduelis carduelis.

A surprise here was that the breast of the male Bullfinch Pyrrhula pyrrhula reflected UV suggesting,

if the above is correct, that carotenes are probably a constituent of the breast colour (redness, as in

Robins, is produced by dominance of melanins). The contention that carotenoids are a constituent

of a bullfinch’s breast colouration has been confirmed by paper entitled: ‘Carotenoids in bird

plumage: the complement of red pigments in the plumage of wild and captive bullfinch’ Stradi et

al 2001 Comparative biochemistry and physiology Part B Biochemistry molecular biology Vol: 128,

Issue 3, pp: 529-535.

Another highlight of this study was seeing how blues reflect UV. Indeed, as shown, in the images of

a Jay’s Garrulus glandarius wing and the back of the Kingfisher Alcedo atthis, both positively beam

in UV. It is an unanswered question, why these, and no doubt, other species, have evolved to be so

noticeable. Further, white also beams in the UV, and white is even more ubiquitous on birds, not to

mention carotene based colouration that also makes birds stand out.

This result confirms the contention that, in general, there is no ‘secret’ pattern that cannot be seen

by humans, but instead, the ability to see in UV increases the contrast and clearness of the sight in

birds.

This sharpening up vision using the ability to see in UV, along with all the other visual abilities,

mentioned above, that birds can call upon, belongs, therefore, to a suite of visual aids that gives

birds significantly better vision than their mammalian counterparts.

The questions keep coming

Although this study confirms that there is no specific UV pattern that manifest in feather

reflectance, some intriguing questions have emerged.

Carotenes reflect UV, so why do yellow, carotene based, irises, absorb UV, as in the Scops Owl Otus

scops in this article, and also confirmed in the Sparrowhawk Accipiter nisus by the author?

Blue, particularly metallic blue, such as in the Jay and Kingfisher positively beam in the UV. Why

would feathers evolve to be highly visible for all to see? In these two species the argument of sexual


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selection, i.e the females chose the more colourful males, does not work as the sexes have the

same colouration (isomorphic). Indeed although there is a large literature dealing with mate choice

it still remains a mystery in both isomorphic (birds where the sexes are the same, e.g kingfishers),

and dimorphic species (where sexes are visually significantly different).

Indeed, I have recently received a paper mapping the eye movements of Peahens Pavo cristatus

when observing Peacocks displaying, (‘Through their eyes: selective attention in peahens during

courtship’, Jessica L. Yorzinski et al, The Journal of Experimental Biology 216, pp3035-3046, 2013),

and these data suggest that peahens take very little notice of the upper tail display!

Go figure.

White is very common on many species, the same question arises as with blue with regard to high

visibility.

The amazing colours, with white being one of those colours, found on some bird species, is

difficult to explain from a functional point of view. It certainly makes them more visible, so being

camouflaged by blending in with the vegetation is not the function. LBjs have got that right when

it comes to camouflage.

This study also suggests that:

In feathers, all melanins absorb and all carotenes reflect UV.

This would be interesting to confirm or deny.

The search for answers continues.

Richard Melzack Ph.D


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Hertfordshire and Middlesex Wildlife Trust is a charity dedicated to protecting wildlife and wild

places for everyone for the future. We have 21,000 members and are one of 47 local Wildlife Trusts

across the UK.

We safeguard and manage 44 nature reserves. Our vision is for an environment rich in wildlife for

everyone. Our mission is to protect wildlife, restore biodiversity and to connect people with the

natural world in Hertfordshire and Middlesex.

Our aim is to be the most active and influential wildlife champion in the counties.

Elstree Aerodrome

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Flying club

Tern rafts

Southfountain

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Vegetation cleared in 2011

Feeding site

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Pond

Hilfield Park Reservoir

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