volunteer magazine 2015

From the British Trust for OrnithologyMaking a real difference for birds

Make 2015 the year of the house Martin!

They share our homes, yet remain mysterious: We need YOUR help to unlock their secrets

LocaL bird cLubs work together

garden birdwatch miLestoneWe celebrate the first 20 years and look to the future

first results from the Winter Thrushes survey

a successful small-scale study of Corn Buntings

waLking in a winter wonderLand

BTO Volunteer Magazine | 20152

Editorial

...i’m not the best birdwatcher in the world – i mistake flying Woodpigeons for Sparrowhawks, get confused by reed Warblers and Sedge Warblers when they first arrive and i’m absolutely hopeless at gulls. Every spring i am consumed by a new determination to improve my bird id skills – “this

year i’ll nail it” i tell myself. to make matters worse, i’ve just found out that i am ranked at number 25 in the Bto staff chart for the number of ‘complete lists’ added to Birdtrack in 2014 – not a great performance! These things bother me a bit because i know i could do much better if i had more time, commitment and determination.

if you feel a bit like me, join me and give it another go this year. Here are some of the tools i’ll be using to help me along: firstly, i’ll be making frequent use of the Bto Bird id video tutorials – they’re free and cover a wide range of confusion species including Mistle and Song Thrush, Willow Warbler and Chiffchaff and Common and arctic tern. i find a quick refresher before or after an encounter really helps me to seal my learning in.

The second thing that helps me is the practice of taking part in surveys or more informal recording schemes like Birdtrack. Forcing myself to work at identifying species in order to record them accurately pushes me that bit further

with my identification skills. it also helps me to notice more about the context of my sightings and my experience is that the surrounding habitat, sounds, behaviour, time of day etc. all add up to paint a more complete picture, which makes identification easier and more memorable. Surveys can also stretch our knowledge by, for example, forcing us to look at a specific species or a specific part of a species’ lifecycle, as the House Martin Survey will do this year. if you struggle with telling House Martin from Sand Martin or Swallow, this year could be a great year to finally crack it (and there’s a video tutorial for that too, by the way!).

Bto is very lucky that not all of its fantastic volunteer birdwatchers are like me but we can all contribute in our own ways to the important evidence needed to conserve our birds and wildlife. inside you’ll find information about a range of ways in which you can play your part, whatever your experience or skill level. You’ll also find updates on recent surveys, plans for upcoming surveys and news on how survey data are being used. However you support our work, i hope you enjoy this magazine and that it inspires you to get stuck in for birds!

Thank you,

A grand total of 224 species were recorded by volunteers doing the Breeding Bird Survey in 2013. The average number of species recorded in a square was 31, but the record went to a square in the Lune Valley, Lancashire, where 77 species were recorded!

Three migrant birds which winter in the arid zone of Africa have shown significant increases between 1995 and 2012. UK Breeding Bird Survey trends for Reed Warbler have increased by 21%, Whitethroat by 35% and Redstart by 45%.

A Buzzard ringed as a nestling in Cumbria in 1985 reached the grand old age of 28 years, 1 month and 11 days before being found freshly dead in 2013, just 12km from where it was ringed. An Avocet ringed in a nest in 1990 was reported alive 22 years, 7 months and 23 days later in 2013.

Over 3,000 volunteers contribute to the Wetland Bird Survey (WeBS) at over 2,600 sites across the UK. WeBS is the principal scheme for monitoring the UK’s wintering waterbird populations, providing an important indicator of their status and the health of wetlands.

In 2014, more than 1,000 volunteers monitored over 45,000 nesting attempts through Nest Box Challenge and the Nest Record Scheme. The Nest Record Scheme is now in its 76th year and in that time over 1.35 million nest records from 232 different species have been sent in.

WElCoME...

dId yOu kNOw?

Ieuan Evans Associate Director Communications – Engagement

2015 | BTO Volunteer Magazine 3

ContEntS

CONTACT uS

BTO, The Nunnery, Thetford, Norfolk, IP24 2PU Telephone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .01842 750050 Facsimile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .01842 750030E-mail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.bto.org

BTO Scotland, Cottrell Building, University of Stirling, FK9 4LATelephone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 01786 466560Facsimile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 01786 466561E-mail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]

BTO Cymru, Thoday Building, Deiniol Road, Bangor, Gwynedd, LL57 2UWTelephone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 01248 383285E-mail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]

The BTO promotes and encourages the wider understanding, appreciation and conservation of birds. Registered Charity no. 216652 (England & Wales) no. SC039193 (Scotland)

Patron HRH The Duke of Edinburgh, KG, KTPresident Chris PackhamChairman Tony FoxHonorary Secretary Frances HurstHonorary Treasurer John Osmond

BTO VOLuNTEER MAgAzINE

JNCC — All references to JNCC in Volunteer refer to the Joint Nature Conservation Committee, which is the statutory adviser to Government on UK and international nature conservation, on behalf of the Council for Nature Conservation, Natural Resources Wales, Natural England and Scottish Natural Heritage.

Editors Ieuan Evans and Su Gough

Layout, design, imagesetting and typesetting O’Connor Design Consultants

Printing Reflex Litho, St Helen’s Way, Thetford, IP24 1HG

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Welcome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Join Ieuan in increasing your bird knowledge!

Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Recent survey round-up . . . . . . . . . . . . . . . . . . . . . 4News on Nightingales, Woodcocks, NEWS and regional network changes.

Homing in on House Martins . . . . . . . . . . . 62015 is the year of the House Martin Survey and we need YOUR help!

Home-grown science . . . . . . . . . . . . . . . . . . . . . . . . . . 8Celebrating 20 years of Garden BirdWatch and the amazing science it has unlocked.

Woodland soundscape . . . . . . . . . . . . . . . . . . . . . .10Learning bird songs and calls can really help your birdwatching in habitats where visibility can be impeded.

A local perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12How a group of bird clubs got together to find out more about the Corn Bunting.

Understanding our winter visitors. . . .14The first results of the Winter Thrushes Survey are revealed.

Going anywhere this summer? . . . . . . . . . .16Your holiday bird records will be essential for the next European Breeding Bird Atlas.

Busman’s holiday. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18Find out how BTO staff are involved in a range of demographic surveying in their own time.

Butterflies and birds . . . . . . . . . . . . . . . . . . . . . . . . . 20It’s not all about the birds as BBS surveyors contribute to national butterfly monitoring, and find out about a fabulous joint membership offer.

A new chapter for herons . . . . . . . . . . . . . . . . . 22The Heronries Census is about to go online, marking a new phase in our longest running survey, and one that has tracked some surprising changes thoughout its history.

when you have finished with this magazine, pass it to a friend or recycle it.

The views expressed by the contributors to this magazine are not necessarily those of the Editor, the Council of the BTO or its committees. The Editor welcomes any articles on birds.© BTO 2015. Quotations should carry a full acknowledgement.

The BriTish TrusT For orniThology ISSN 0005 – 3392

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Also, in 2013, BtO became heavily

involved in providing impartial data on

Nightingales in relation to the proposed

lodge Hill development in Kent, which

is also the single most important site for

Nightingales in Britain. Of critical importance

was whether or not the site held more than

1% of the uK grand total of singing male

Nightingales since, if it did, the existing SSSI

designation could be extended to provide

statutory protection for the Nightingales.

the high-profile political interest and

perceived opposing controversial moves

to upgrade the site designation or pursue

the development meant that the national

population estimate provided by BtO had to

be sufficiently robust to pass Defra scrutiny.

achieving this has been a time-consuming

process but has resulted in a novel and

highly sophisticated modelling approach,

which will set a new standard for future

surveys.

two papers are in progress for 2015,

the first documenting the new population

modelling approach and the other

examining changes in abundance and

distribution. updates and outputs, including

county population estimates, will be made

available on the survey page: www.bto.org/

nightingale-news

Meanwhile, a preliminary estimate of

approximately 6,000 males in 2012 has

been published on the BtO’s Birdtrends

web pages. this represents a sharp decline

from the 1999 survey, for which population

estimates need to be revised upwards.

catching up with nightingalesrather a lot has happened since the survey was begun back in 2012, say Greg Conway and John Marchant. Firstly, additional surveying was required in 2013 to provide adequate coverage of regions under-sampled in the first year. extra effort was concentrated into Suffolk and essex, where the survey workload had been especially heavy.

BTO/GWCT WOOdCOCk surVey And AnnuAl MOniTOrinG

surVey updATe

The results from 2013 have been analysed and will be published in a paper examining changes in both abundance and distribution since the 2003 survey, including a longer-term assessment of distribution change using Bird Atlas 2007–11 data. a second paper is planned, which will examine changes in habitat use and the potential influence of a

broader range of factors such as deer, disturbance and soil moisture levels. See www.bto.org/woodcock-survey for results and updates.

Annual counts have been undertaken at around 25 sites throughout the period between the 2003 and 2013 surveys and these have highlighted the steady reduction

in breeding numbers, which is a cause for concern. In 2014, the counts continued and the number of sites was increased to 150, which will provide greater capacity for monitoring future changes. More monitoring sites are still needed, so please continue to cover your 2013 survey square, or contact Greg Conway ([email protected]) for details on how to take part.

A preliminary population of only around 6,000 singing male Nightingales was estimated in 2012.

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neWs will repeat similar surveys

undertaken in the winters of 2006/07,

1997/98 and 1984/85. Past results

showed that numbers of ringed Plover,

Sanderling, Purple Sandpiper, Bar-tailed

Godwit and turnstone have fallen on

the Scottish coast, contributing to uK

population declines. Many of these

birds occur in internationally important

numbers, yet the remote nature of

rocky shores and other non-estuarine

coast means it is a habitat which is

poorly monitored by the Wetland Bird

Survey (WeBS). Periodic coverage by

NeWS is therefore a key part of the

uK’s waterbird monitoring programme.

as well as the key waders, NeWS

will include counts of inshore seaducks

and passerines such as rock Pipit,

and collect information on the tidal

wrack resource on beaches. Stretches

of non-estuarine coast will be

allocated to volunteers, and there will

be opportunities for groups of keen

birders to undertake expeditions to

important areas. We anticipate that

some professional fieldwork will be

needed to fill gaps.

Previous NeWS surveys were

primarily funded by the uK’s Country

agencies (nowadays: SNH, Ne, NrW

and DOeNI). Funding for this winter’s

survey has not yet been secured – so

we don’t yet have final confirmation

that the survey can take place but we

will update you as soon as we can.

Some waders, such as Turnstone, are not as frequently encountered on sandy/muddy habitat, preferring rocky shores, but results from WeBS and NEWS show that these species are in decline.

Our volunteer regional representatives (rrs) do a fantastic job representing BtO at the local level, organising surveys, being the point of contact for local members and volunteers, organising events and so much more. Here we thank the rrs that retired during 2014, and welcome aboard the new ones that have joined us.

reTirinG reGiOnAl represenTATiVesArthur Brown . . . . . . . . . . . . argyll (N) 2009–2014Roger Warren . . . Buckinghamshire 2010–2014Mark Eddowes . . . . Cheshire (Ne) 2008–2014 Mark Eddowes . . . . . . . Cheshire (S) 2013–2014Clive Hartley . . . . . . . . . . . . . . Cumbria 2002–2014Alastair Flannagan . . .Glamorgan (W) 2011–2014James Gloyn . . . . . . . . . . Isle of Wight 1992–2014Jean Roberts . . . . lancashire (NW) 2005–2014Steve Suttill . . . . . . . . . . . . . Manchester 2003–2014Bob Proctor . . . . . . . . Moray & Nairn 1994–2014Richard Paul . . . . . . . . . . . . . . Perthshire 2005–2014Harry Green . . . . . . . . Worcestershire 1972–2014

neW reGiOnAl represenTATiVesPhil Tizzard . . . . . . . . . . . . . . . . . . . . . . BuckinghamshireHugh Pulsford . . . . . . . . . . . . . . . . . . . Cheshire (Ne, S)Colin Gay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CumbriaClaire Young . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DorsetLyndon Jeffery . . . . . . . . . . . . . . . . . . . . Glamorgan (W)Jim Baldwin . . . . . . . . . . . . . . . . . . . . . . . . . . . Isle of WightJohn Clarke . . . . . . . . . . . . . . . . . . . . . . . . . . . . londonderryNick Hilton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ManchesterMelvin Morrison . . . . . . . . . . . . . . . . . . . Moray & NairnKen Graham . . . . . . . . . . . . . . . . . . . . . . yorkshire (l&W)Steve Davies . . . . . . . . . . . . . . . . . . . . . . . Worcestershireyou can find out more about the regional Network online (www.bto.org/volunteer-surveys/regional-network) and make contact with your local rr.

VACAnT BTO reGiOnsWe have a number of BtO regions with no rr. If you are interested in taking on the role of rr, or part of the job, please contact Dawn Balmer at BtO HQ ([email protected] or call her on 01842 750050).Scotland: angus, argyll (N), Dumfries (from July), Perthshire, SutherlandEngland: essex (Ne), essex (S), lancashire (NW), yorkshire (Se), yorkshire (SW)Wales: anglesey

From lundy to loch linnhe and Seahouses to Scrabster, plans for next winter’s Non-estuarine Waterbird Survey (NeWS) are taking shape!

nOn-esTuArine WATerBird surVey

news about neWs ChAnGes TO Our reGiOnAl neTWOrk

We have been keen to run this

survey for several years, particularly

after seeing the rapid and dramatic

changes in House Martin populations

and distributions documented by Bird

Atlas 2007–11. Our planning kicked off

in earnest last summer, when we ran

a small-scale pilot survey. Pilot work

allows us to test our methods and make

decisions about what data to collect

and how to collect them. Our pilot

survey enabled us to confirm that the

survey was feasible and to make some

adjustments to the survey methods. We

have also been thinking carefully about

exactly how we will use the data, and

how we can make use of information

collected from other sources such as

land-use data and satellite images.

Choosing the squares

Another important component of survey

planning is deciding which sites to

cover. The main aim of the 2015 survey

will be to obtain a robust population

estimate. There are two broad approaches

to choose from: a census or a sample.

A census aims to carry out a full count

by visiting all sites where a species is

known to occur or potentially occurs.

This is possible for scarcer species which

are restricted by habitat requirements

to a small number of sites. However,

for species with a large and scattered

population like the House Martin, this

approach is not possible.

Instead, a sampling approach is

needed. A small proportion of sites

(usually squares) are surveyed and a

population estimate is calculated, based

on the counts at these sites. In order to

use the counts to produce a population

estimate, it is essential that squares

are picked randomly so that they are

representative of the UK as a whole.

This approach is followed for many BTO

surveys, including the BBS. so many

of you will already be familiar with this

concept.

habitat basis

For single-species surveys, we

sometimes use a ‘stratified sample’,

grouping squares into different

categories (often based on habitat), and

select a proportion of squares from each

category to ensure we cover all suitable

habitats. House Martins are most likely

to breed in small villages or close to the

edge of towns, but they can also be

found at sites ranging from dense urban

centres to isolated farmhouses, as well

as coastal and inland cliffs. Our survey

will therefore need to cover a wide range

of habitats including some of these

extremes.

This variability presents us (and our

volunteers!) with a challenge – some

1-km survey squares will contain only a

couple of houses and will take just a few

minutes to survey, others will be entirely

urban and may take several hours to

cover thoroughly.

bto Volunteer Magazine | 20156

House Martin survey

House Martins

Planning for BTO surveys starts well before fieldwork can take place, to ensure the survey methods are clear and interesting for our volunteers, yet also scientifically rigorous. More pragmatically, we need to ensure that we can fund any survey. Thanks to the generous donations you made in response to last autumn’s House Martin Appeal, we can go ahead with the UK House Martin Survey this year. Survey organiser Ian Woodward brings us up to speed.

Homing in on

“Our pilot survey enabled us to confirm that the survey was feasible and to make some adjustments to the survey methods.”

We need your help!

A robust population estimate from

random sample surveys can only be

made if good coverage is achieved and

no bias is introduced because volunteers

select what they perceive to be the better-

quality squares. As always, we are relying

on our excellent network of volunteers to

achieve good coverage. You can choose

a square by visiting our website (www.

bto.org/house-martins). If it will take only

a few minutes to cover all of the suitable

habitat available in your square, please

have a look to see if you can take on a

second square.

Bias can also be introduced because

there are fewer people in some parts

of the UK, making it harder to achieve

full coverage in these areas. We can

sometimes control for this sort of bias

during our analysis, but it is better to

resolve it up-front by surveying more

squares in all regions. If you are going on

holiday in the UK in June, please check to

see if you can cover a square near to your

holiday site. A single visit in June will be

better than no visits at all.

Whilst we expect many squares will

contain House Martins, occupancy is

unpredictable even in the higher-quality

habitat, so we know there will be some

squares without any House Martins. We

know how frustrating it can be to travel to

carry out a survey and not find the target

species. However, even if your square has

no House Martins, these zero counts are

extremely important to produce an accurate

population estimate, so by submitting your

zero count you will be making a valuable

contribution to the survey.

2015 | bto Volunteer Magazine 7

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“Whilst we expect many squares will contain House Martins, occupancy is unpredictable even in the higher quality habitat.”

The House Martin Survey has been timed to coincide with the incubation and provisioning of the first brood. Once these have fledged, recordind can get very complicated, with juveniles returning to the nest to help with later broods.


Garden BirdWatch

celeBratinGtWenty years ofscience in your

Gardens There have been big changes at our winter feeding stations over the last 20 years, with new species, such as Blackcap, becoming familiar sights.


Garden BirdWatch

There were predecessors to GBW. The

Garden Bird Feeding Survey started in 1970,

but due to the lack of external funding, the

numbers of participants had to be limited.

The BTO then managed to secure short-

term funding for other garden surveys (BTO/

BASF Garden Bird Survey and BTO/IWC

Garden Bird Enquiry). Eventually, with core

funding from CJ WildBird Foods Ltd and

the generosity of BTO supporters, Garden

BirdWatch was launched and, by the end

of 1995, an astonishing 5,028 people had

signed up; 708 of those are still contributing

records to this day.

For many who joined in 1995, recording

birds for GBW seemed like a natural

progression as they were already noting

down their garden birds. One Garden

BirdWatcher from Gwent told us that “as soon

as I read about GBW, I realised that it was

exactly what I’d been waiting for – a chance

for my birdwatching to be of use.” Since

then he has submitted the most records

from a single site, with his highlight being a

Hawfinch – the first he’d ever seen, despite

looking for it in a number of woods!

fascinaTing findings

Thanks to 94.7 million species observations

(from 7.3 million weekly submissions), GBW

data have been used to show a variety of

fascinating things. These include determining

seasonal patterns, such as the autumnal dip in

Blackbird reports, how the weather can affect

garden use, such as the phenomenal rise in

reports of Blackcap during the cold weather

in March 2013, and how garden use has

changed over the last 20 years. Goldfinches

were reported from an average of only 12% of

GBW gardens in 1995 but, by 2012, an average

of 63% of gardens had reported them. This

increase in garden use has been attributed

to changes in the food that we provide for

birds, with nyger seed and sunflower hearts

becoming more common food items and

much to the Goldfinches’ liking.

Sadly, Garden BirdWatchers have also

charted the decline of some of our well-

known garden bird species. While some,

like House Sparrow and Starling, have been

declining since before the survey started,

others, including Greenfinch, have had

their population crashes tracked by GBW.

For Greenfinch, BTO scientists were able

to pinpoint when the population started

to decrease by combining GBW data with

information from the Garden Bird Health

initiative. This study revealed that the disease

trichomonosis, originally known from pigeon

species, started to affect Greenfinches

in 2005 and they have been declining

in gardens ever since, reflecting what is

happening in the wider countryside.

Gardens are often the place where people first encounter birds and other wildlife and learn to love them, says Clare Simm. In addition, gardens are an important habitat supporting a wide range of species. Back in

1995, when Garden BirdWatch (GBW) started, gardens were less appreciated, meaning that funding for garden surveys was hard to come by; so, it is thanks to our supporters that we have made it to our 20th anniversary.

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Thanks to the enthusiasm of Garden

BirdWatchers, we have also been able

to run one-off surveys to answer other

scientific questions. The Shortest Day Survey

was run in December 2004 to investigate

whether there is a pattern to the time at

which different bird species arrive at garden

feeders on a winter’s morning. 5,460

people participated, including a sizeable

number of Garden BirdWatchers, and it was

discovered that the time at which garden

birds begin to forage on winter mornings

may be limited by their visual capacity at

low light intensities. It was also found that

birds appeared at garden feeding stations

later in the morning in urban areas than

in rural areas during the winter. This latter

finding prompted us to run the Early Bird

Survey in January 2014, to investigate

whether light pollution has any effect on

the foraging behaviour of garden birds. The

results from the latter survey have just been

submitted to a peer-reviewed scientific

journal for publication.

siMple Things

In the 20 years of GBW we have had

a phenomenal 481 different species

recorded. One garden in Cumbria has

recorded 167 species, including Water

Shrew and Grasshopper Warbler. While

seeing unexpected species is a buzz for any

Garden BirdWatcher, many of them told us

that it is the simple things that keep them

hooked. One, from Gloucestershire, said “It

[GBW] provides an opportunity to watch bird

behaviour – the reaction when a Sparrowhawk

is about, the ‘pecking’ order between species,

the arrival of Blackcaps in winter compared

with timings in previous years…”

It is the long-term records of common

species that have allowed us to find out as

much as we have, so a huge thank you to

those who currently take part in GBW and

those who have taken part in the past – your

time and devotion are much appreciated.

Want to know more about GBW and the birds that use your garden? Visit www.bto.org/gbw.

One change over the 20 years is the now-frequent visits of Long-tailed Tits to feeders.

As we set off through the fresh green

morning, we are surrounded by mature

broad-leaved woodland, with the sun filtering

down through the new leaves. Away from

the path the ground is almost devoid of

plants, but there is vegetation from shoulder

height and upwards to the tops of the

trees. Common birds are all around and will

accompany us on the whole of our walk:

the short, sweet, melancholy phrases of

Robin; the melodic, thin, metallic song of

the Dunnock and the fluty, rich and luscious

Blackbird song. Almost at once we spot a

small warbler high in the tree tops. From this

distance and angle there is no way

we could look at the leg colour

or ‘primary projection’, however, the simple

repetitive ‘chiff-chaff’ song immediately gives

its identity away!

Another frequent song is the bell-like

ringing ‘teacher-teacher’ of Great Tit, but a

sudden sneezed ‘pit-chou’ alerts us to the

presence of a Marsh Tit. This is the call, and

we probably won’t hear Marsh Tits singing

today as, for them, the breeding season is

already well advanced. As we move past one

large tree a loud ‘kek, kek’ echoes around

and we stop and wait until the Great Spotted

Woodpecker moves around the trunk and

reveals itself – a stunning male with his red

nape patch. Then we realise that he has his

nest hole high on the same tree – the young

are calling from within. We move on, to allow

the adult to feed his chicks in peace.

drAmAtic Action

A thin, high ‘shree-shree-shree’ call emanates

from another trunk and we turn to scan the

tree with binoculars, finally spotting the small

mouse-like Treecreeper heading up the trunk.

We would have missed it completely if we

hadn’t heard it first! Suddenly there is a burst of

very high-pitched simple ‘seeet’ whistles from

the birds around us and, recognising this as the

‘avian predator alarm call’ of many small birds,

we look around for the cause. We’re rewarded

with the sight of a silent female Sparrowhawk

flashing fast and low through the trees.

Panic over, the birds return to more relaxed

behaviour. Suddenly, a loud ‘kee-kee-kee-

kee-kee-kee-kee-kee-kee-kee-kee’ call echoes

out, and we wonder if the Sparrowhawk has

returned but the relaxed behaviour of the

tits suggests otherwise and our curiosity is

rewarded with splendid views of a Lesser

Spotted Woodpecker; their raptor-like call is a

good one to learn! We make a mental note

to look more closely at the foraging mixed tit

flocks which roam through these woodlands

in winter – these diminutive woodpeckers

have a habit of joining them.

We carry on walking, entering into an

area with large conifers. The feel of the wood

changes completely, as do the sounds we

are hearing. The most frequent are short,

soft contact calls, but we are not confident

to identify these until one of the birds starts

singing, a jaunty hop-skip ‘dee-d-lee-dee-d-

lee’ with a finishing flourish – confirming the

Bto Volunteer magazine | 201510

Bird identification

a springtime soundscapea walk in the woods:

One of the greatest birding joys is a walk through spring woodland, soaking up the sights and sounds as our birds enter the breeding season. Birdwatching in woodland can be

frustrating, however, as the birds often remain resolutely hidden behind the new spring leaves. Being familiar with their songs and calls will equip you with a whole new way of

both finding and recognising birds, and might help you home in on a target species. Come with Ben Darvill and Su Gough on a walk through the woods to see this in action…

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Stock Dove is often over looked as a Woodpigeon, unless its distinctive song is known.

Birdwatching in woodland can be frustrating, but easier if you let the songs and calls help you.

Visit the

online version of

this article to

hear

the bird sounds

described!

As we walk into the more open area

there are piles of brash lying around and a

machine-gun-like song resounds from low

down in these piles. it’s a Wren – one of

the loudest birds for the size of its body.

There is a different warbler singing from the

shrubs in our wood – a beautiful, complex,

rich and fluty song. The big question – is

it a Blackcap or Garden Warbler? A difficult

one this, but the bird in front of us is singing

with a steady pace and the ‘verses’ seem

well-practised and not over-long. Each phrase

seems to start tentatively but finish in a rich

and confident manner. We are pretty certain,

therefore, that we are listening to a Blackcap.

birds as Goldcrests. We hear ‘teacher-teacher’

again, but this time the song lacks the strength

and bell-like ringing quality heard earlier,

instead sounding weaker, reedy and slurred,

identifying the bird as a Coal Tit this time, the

difference in quality of song being the clincher.

helping to tArget

We move out into a more open shrubby area,

but there is a stand of Douglas Firs on the

edge of the conifer patch and it’s in this area

that we hope to catch up with one of our

target species. A few moments scanning the

trees for movement produces nothing. Then

we hear another Goldcrest singing. But wait!

is it a Goldcrest? The song is similar (it’s clear

and high-pitched), but it lacks the jaunty hop-

skip notes, sounding more like an accelerating

‘dee-dee-dee-dee-dee-dee’ with a less

flamboyant finish. Finally we see movement

low down and watch through binoculars as a

beautiful male Firecrest emerges briefly but,

thankfully, for long enough to see the face

stripes and chestnut shoulder patch. Excellent!

The bird does not reveal itself, however, so

there’s still a little doubt in our minds.

A maniacal laughing call is much easier to

identify: a Green Woodpecker ‘yaffling’ and,

as we walk around the corner into a grassy

clearing, we interrupt its Wood Ant meal and it

bounds away up into the trees. We are back in

broad-leaved woodland now, and a large bird

passes overhead, silhouetted against the sky.

it calls, a cat-like mewing: a Buzzard. Just as

we leave the wood, a low distinctive ‘whoo-

whoo-whoo’ draws our attention to a pair of

Stock Dove perched in one of the larger trees

– we could easily have missed them amongst

all of the Woodpigeons, if their song wasn’t so

distinctive.

A great walk, which was enhanced by

our ability to identify at least some of the

species we heard by sound. you never stop

learning, however, and this is one of the joys

of discovering bird songs and calls, there are

always new species, new sounds and even

familiar species making a sound you have

not encountered before.

2015 | Bto Volunteer magazine 11

Bird identification

If you’ve been inspired to improve your knowledge of bird songs and calls, here are some top tips.

Access the online version of this article and listen to the songs and calls that we’ve featured. Visit www.bto.org/woodland-song.

Invest in an audio-guide which is optimised for learning. Geoff Sample’s Bird Songs and Calls is recommended. The 3-CD set takes you through different habitats, allowing you time to try identifying each species before the narration gives you the right answer.

Test yourself. Why not stop for a minute when you’re out on a walk and actively listen. You could even shut your eyes. Try and identify everything that you can hear, then use your binoculars to search out those species that you were uncertain about.

Make up your own mnemonics - you’re more likely to remember yours than other people’s. For example, Ben remembers Chaffinch song as ‘ha ha ha ha, ha ha ha ha, ha ha ha! I shot you!’ It works for him!

HoW To Tune In…

“There is a different warbler singing from the shrubs in our wood – a beautiful, complex, rich and fluty song. The big question – is it a Blackcap or Garden Warbler?”

Learning songs and calls can help your birding in numerous ways, including enabling you to go into an area armed with another way of locating and identifying a target species, such as the scarce and elusive as Lesser Spotted Woodpecker.

The Herts Bird Club has a long history of

monitoring breeding Corn Buntings and so

welcomed the opportunity to work together

with the Bedfordshire and Cambridgeshire

Bird Clubs to design and run a survey of

the species. With plenty of enthusiastic local

volunteers, this was a good opportunity

to provide interest for local birdwatchers

and contribute some useful information

about this enigmatic species in one of its

strongholds in eastern England.

Results from recent tetrad-scale atlases

in the three counties identified reductions

in the distribution of Corn Buntings of

between 27% and 62% over the past

20 years – but these projects were not

designed to measure population size in the

way that a targeted survey could. The atlas

fieldwork however did provide useful clues

about where to focus our volunteer effort.

By randomly selecting a fifth of the tetrads

(2-km x 2-km squares) where birds had

been located in recent breeding seasons,

surveyors could have a reasonable degree

of confidence that they would find the target

species. Data from the previous atlas period


Focus on Volunteers

a loCal pERspECTivERecent years of atlas fieldwork uncovered many birdwatchers who had not previously participated in surveys and were keen to contribute to our understanding of changing bird populations. Chris Dee, BTo Regional Representative for Hertfordshire, describes how three neighbouring bird clubs collaborated to harness this untapped potential for a Corn Bunting survey in 2014.

focusing in on the details

corn Buntings are declining in range but in favoured locations

can still be found at high densities. Joining in a local

bird club survey can help us to understand more at a fine scale.

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Corn Buntings:

(1988–92) were also used to provide a

smaller sample of tetrads (10%) from which

birds had recently disappeared. The aim

was to cover 146 tetrads across the three

counties whilst giving the more enthusiastic

volunteers the flexibility to take on extra

squares.

We built a website to show the survey

squares and provide printable survey forms

and the survey was publicised through

the bird clubs’ websites and at meetings.

advice on survey timing was sought from

Rosemary setchfield who has been working

on Corn Buntings in north Hertfordshire

with the RspB. We asked volunteers to visit

their chosen locations on two occasions;

once in the first three weeks of June

and once in the first three weeks of July,

plotting the position of all Corn Buntings

on the maps provided.

There was a very positive response

from local birdwatchers; 91% of the priority

tetrads were surveyed and a further 66

extra squares were also visited. analysis

is currently under way, with the hope that

the results can help to identify population

hotspots that could be targeted for agri-

environment advice.


Focus on Volunteers

WOrking TOgeTHer lOCally

The Three Counties Breeding Corn Bunting Survey is an excellent example of local bird clubs working together to discover more about a species with the aim of establishing the population size, which may well lead to local conservation action.

Although the BTO is able to organise periodic UK single-species surveys in addition to our core monitoring schemes, there is still much that can be learnt through local co-ordinated fieldwork. The most recent published assessment of population estimates of birds in the UK highlighted many opportunities for volunteers to make a significant contribution to our knowledge.The report identified a suite of species for which better local population density estimates would greatly aid the difficult task of estimating population size. Examples of species suitable for small-scale local studies

include: Breeding ducks such as Mandarin, Gadwall, Teal, Eider, Red-breasted Merganser, Goosander.

Breeding waders, especially in the uplands. Breeding owls and birds of prey such as Little Owl, Tawny Owl, Hobby, Kestrel.

Breeding Water Rail, Rock Pipit, Kingfisher, Sand Martin, Black Redstart, Willow Tit, Lesser Spotted Woodpecker.

Widespread wintering species such as Yellowhammer, Water Pipit.

Wintering waterbirds in the wider countryside such as Mallard, Moorhen.

If you’re interested in co-ordinating a local small-scale study and would like some advice on methodology, BTO would be keen to support you. Please contact Dawn Balmer ([email protected]).

Identify a species that local atlas work has shown to be in decline or a county BAP species, but not one that is so scarce that volunteers are unlikely to find it.

Investigate collaborations with other local bird groups.

Decide on survey methods and sampling strategy, consulting with experts or published literature. Decide what will be counted, when and in what size survey areas.

Select areas to be surveyed; random sample, stratified random sample based on prior distribution knowledge or habitat features, or a complete survey of the entire area. Tailor this based on an estimate of how many birdwatchers may participate.

Determine a way to allocate survey plots to observers to avoid duplication of effort, through local organisers or a

website or web page. Publicise the survey through local bird club websites, meetings, newsletters and social media.

Distribute instructions and survey forms in good time.

Provide feedback at the end of the fieldwork season.

Write up the results for local bird report or even a national journal.

TIPS fOR RUnnInG A LOCAL SURvEY…

“There was a very positive response from local birdwatchers; 91% of the priority tetrads were surveyed and a further 66 extra squares were also visited.”

The survey ran over two winters

(2012/13 and 2013/14), and data were

collected by 1,957 BTO volunteers from

more than 4,000 unique 1-km squares

within the UK. Many surveyors visited their

squares multiple times throughout winter,

providing vital information on how the

habitat usage and food preference varied

through the winter months.

The survey data are being used to

investigate two key questions, both still in

progress:

Determining a population estimate

for winter thrushes in the UK, using count

data from ‘core squares’ that were surveyed

between December 27 and January 10. The

abundance data collected during this core

period will give us an estimate of the total

number of thrushes present in the UK at

this time of year.

Investigating between-species and

geographical differences in the use of

foraging habitat and food preferences

throughout the two winters, to help identify

key resources and potential factors in the

patterns of change observed in numbers of

breeding and wintering thrushes.


Winter thrushes survey

WinterVisitors

Thousands of thrushes migrate to the UK from mainland Europe to take advantage of our relatively mild winter conditions. But precisely how many come, how they are distributed around the UK, and what they feed on whilst they are here is not well known. The Winter Thrushes Survey was designed with these questions in mind and ecologist Kathryn Ross has been delving into the data.

Fig 1 Foraging habitat preFerences For the Five winter thrush species

FieldFare

habitat Key

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Data from the 2012/13 and 2013/14 winters were combined to show the proportion of foraging observations occurring in each habitat each month.

amenity land

brownfield/industrial

coastal habitats cropped farmland

Moorland/heath open parkland orchard pastoral land private gardens

woodland

blacKbird

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nov

dec

Jan

Feb

Mar

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FieldFare Mistle thrush

proportion oF observations

redwing song thrushBlackbird Fieldfare Mistle Thrush Redwing Song Thrush

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OCT

SEP

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Proportion of observations

Habitat

Amenity land

Brown�eld/industrial

Coastal habitats

Cropped farmland

Moorland/heath

Open parkland

Orchard

Pastoral land

Private gardens

Woodland

Foraging habitat preference in each month

0.25

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Where dO Thrushes feed?

So far, we have found that the habitats

used for foraging vary between species and

throughout the winter (Fig 1). For Redwing and

Fieldfare, pastoral land increases in importance

as the winter progresses. Fieldfare were

more reliant on pastoral land and cropped

farmland than other species, and this habitat

specificity was even more pronounced in the

spring months. In contrast, for Song Thrush,

Mistle Thrush and Blackbird (which are back

on territories and starting to breed by March

in the UK), use of pastoral land appears to

lessen in April. Blackbird showed less variation

in habitat preference throughout the survey

period compared with the other species, with

private gardens, woodland and amenity land

remaining important throughout the winter

period. The geographical variation in these

habitat preferences is still being investigated.

acKnowledgeMents The Winter Thrushes survey was funded by members and volunteers through the BtO raffles in 2011/12 and 2012/13 and generous donations from charitable trusts:The benham charitable settlement/The Mitchell trust/Keith ewart charitable trust/The saxham trust/The harris charitable trust/Marjorie coote animal charity trust


Winter thrushes survey

conservation oF thrushes

breeding populations of thrushes in the uK are significantly lower than they were in the 1970s, although the trajectory of change has varied between species. blackbird and song Thrush numbers declined steeply throughout the 1970s and 1980s, levelled off in the mid-1990s with a period of increase between 1995 and 2005; but a downward trend has again been observed in more recent years. Mistle Thrush, on the other hand, has declined steadily since the 1970s, with no indication of levelling off. The reasons for these declines are not well understood but reduced survival of first-year birds and shifting of populations due to climate change may play a role.

while Fieldfare and redwing are ‘red listed’ in the uK according to the birds of conservation concern criteria, this is on the basis of changes in our very small breeding populations of these species, so it tells us nothing about the much larger

european populations that breed on the continent and visit the uK in the winter. according to the pan-european common bird Monitoring scheme (pecbMs) data, redwing populations throughout europe are relatively stable, but Fieldfare has suffered a moderate decline in the last two decades.

song Thrush is on the uK red list due to its declining breeding populations, while Mistle Thrush is currently amber listed and continuing to decline. For these species, where there is considerable overlap between the uK breeding and wintering populations, changes in winter survival are likely to impact the breeding population numbers. The more informed we are about foraging habitat, food preferences, and the availability of these resources throughout the winter, the more we can do to ensure that the right sort of habitat and resources are available at the right time of year to sustain our winter thrushes.

Mistle thrush

This first atlas has proved a powerful

tool for conservation, for identifying

hotspots, addressing the impact of

changes in climate and land-use and for

assessing the effectiveness of conservation

action. New data are now needed to

address emerging conservation issues, and

birds have proved themselves very useful

proxies for biodiversity more broadly.

EBBA2 will:

Provide better, more accurate up-to-date

distribution maps for all breeding species

in Europe.

Show patterns of relative abundance

at a European level for the first time.

Show changes in species distributions

since the last atlas.

Build capacity for conservation and

monitoring in areas of Europe where this

is most needed.

The project is led by the EBCC and its

partner organisations and the geographical

scope encompasses all of Europe including

Turkey and European Russia. The extended

geographical scope brings exciting new

species such as Brown Fish Owl and

Grey-necked Bunting to a list that currently

extends to 582 native and 63 non-native

species. The focal period for data collection

is 2013–17 and, at a minimum, data will be

needed for each 50-km x50-km square for

comparison with the last atlas. The new atlas

will ultimately be presented in a book and

will embrace the new digital world, making

interactive maps and additional material

available online in a valuable resource for

future research and conservation action.

As you can imagine, there are huge

logistical challenges, particularly in

achieving coverage where there are very

few birdwatchers. One of the most valuable

legacies of the first atlas was increased

co-operation across the European

ornithological community. This has

strengthened since, with new conservation

and birdwatching organisations in countries

in the east and south of the continent

and the development of common bird

monitoring programmes in countries from

Poland to Bulgaria.

WhaT can you do To help?

All UK bird records (particularly those with

breeding evidence) collected by schemes

such as BirdTrack, NRS, the Ringing Scheme,

BBS, periodic surveys and the Rare Breeding

Birds Panel will be used and extremely

valuable.

However, you can also help if you

are outside of Britain and Ireland. Every

spring and summer thousands of UK

birdwatchers spread out across Europe

in search of sun, new experiences and

exciting birds. Whether grabbing an hour

or two around a Mediterranean salt-pan or

exploring high Caucasian peaks in search

of Great Rosefinches, all birders abroad

can help.

As with Bird Atlas 2007–11, there are

two main ways to contribute:

Submit any non-standardised bird records

(akin to roving records) which must include

the date, geographical location, name and

contact details of the observer and any

evidence of breeding. Lists of all species seen

in a 50 x50-km grid, or smaller area, are also

extremely valuable.

Do a standardised or timed survey.

Methods for these vary between countries

and observers are recommended to contact

national co-ordinators in priority countries

(available on the EBCC website www.ebcc.

info/index.php?ID=545). Where this is not

possible, the best option is a complete species

list from a timed (1–2 hour) visit to a specified

geographical unit, such as 1 x 1-km, 2 x 2-km,

or a route.

One of the easiest ways to contribute

records is to use BirdTrack. This free system

now allows users to submit data from

anywhere in the world. All breeding bird

data submitted via BirdTrack will be made

available to EBBA2 and national atlases, as

will data from most of Europe’s other online

bird-recording systems. Otherwise, roving

records or species lists from timed visits can

simply be sent in a spreadsheet to national

co-ordinators or directly to the EBCC.

Here’s your chance to get an atlasing fix,

explore exciting parts of the continent, see

great birds and help a vital project at the same

time. Advice for travelling birders is available at

the EBCC website and 19 countries in eastern

and south-eastern Europe have appealed

for particular help. National co-ordinators for

these countries would be delighted to hear

from observers, from groups and from tour

operators who are interested in contributing.

We have already seen special expeditions

by German birders to Albania, Czechs to

Macedonia and Moldova, and Catalonians to

Montenegro and Turkey: what can the Brits

contribute?

BTo Volunteer Magazine | 201516

Bird recording in europe

The new european Breeding Bird aTlasThe European Bird Census Council (EBCC) has embarked on an ambitious new project to produce the second European Breeding Bird Atlas (EBBA2), reports David Noble. The original ground-breaking book, organised by the EBCC and edited by Ward Hagemeijer and Mike Blair was published in 1997 and collated information from birdwatchers in order to map the distributions of all of Europe’s breeding birds.

2015 | BTo Volunteer Magazine 17

Bird recording in europe

Kentish Plover

sardinian Warbler

CretzsChmar’s bunting fan-tailed Warbler

PurPle gallinule

White-throated robin

ortolan

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slender-billed gull

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birding in europe is hugely popular, with a wide range of species present. if you visit anywhere in europe over the next few years your records will be valuable for the second European Breeding Bird Atlas. Put your records into birdtrack and remember breeding evidence.

…including many staff members, for

the allure of the field is greatly exacerbated

by the day job; there’s no better incentive

to get out and collect data than amazing

volunteers telling you about their fantastic

projects all day. Of the 113 current BTO

employees, 44% are either qualified

or trainee ringers, so the capacity for

demographic monitoring of populations is

considerable and the birds of Breckland

provide an excellent weekend focus.

The original aim of the Ringing Scheme

was to explore movements of birds and,

while advances in tagging have greatly

increased our knowledge of migration routes

and destinations, the fitting of metal rings

still constitutes a valuable tool for studying

dispersal. However, the principal use of ringing

data in the 21st century is to estimate survival

rates which, in conjunction with productivity

data provided by the Nest Record Scheme

(NRS www.bto.org/nrs), help to identify the

causes of population increases and declines.

The less Things change

Interpreting ringing data is much more

straightforward if the effort invested doesn’t

vary over time, as surviving birds have the

same chance of being detected from one

year to the next. Changes in the numbers

handled also become meaningful indicators

of abundance and breeding success rather

than simply reflecting hours in the field. This

is the ethos behind the Constant Effort Site

(CES www.bto.org/ces) scheme, where the

same mist nets are erected in the same

places at the same times each year.


LifecycLe

DemographyThere may be snow on the ground as Ruth Walker and Dave Leech

write, but many species are already gearing up for the breeding season. Dunnocks and Song Thrushes have been in good voice for some weeks, with Great Tits a recent recruit to the chorus. And as

the birds start to stir, so too do BTO volunteers…Ju

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The Breckland region is littered with

staff-operated CES, the longest-running being

Peter lack’s site at lackford lakes, initiated in

1995. Stephen Baillie’s site at Redgrave and

lopham Fen followed in 1997, with the BTO

Nunnery reserve two years later. Hinderclay

Fen and Cranwich gravel pits were both added

to the list in the last decade. Given these are

predominantly wet scrub and reedbed sites, it’s

no surprise that a lot of Reed Warbler data are

collected, but good numbers of other migrant

(Chiffchaff, Blackcap, Garden Warbler) and

resident songbirds (Blue Tit, Wren, Dunnock)

are also encountered.

haVe we MeT BefOre?

using mist nets to sample bird populations

purely by chance interception, as on CES,

works only for some species (generally

smaller ones) in some habitats (generally

those with taller vegetation). Retrapping

Adults for Survival (RAS www.bto.org/

ras) projects often employ colour-rings,

enabling birds to be identified individually

from a distance and their progress

followed. Colour-rings must be easily

viewed if sufficient data are to be collected

and this technique can be particularly

effective in towns, where birds are close

and habituated to people, as Allison kew

and lee Barber have both demonstrated

in Thetford, focusing on Blackbirds

and Woodpigeons/Collared Doves

respectively. Incredibly, Allison’s project

has demonstrated that over 100 breeding

adults visit their small suburban garden in

a single breeding season. lee also leads

on a study of Greylag and Canada Geese

in the town, the birds having been fitted

with neck collars, clearly visible even

when they are on the water; while many

hang around on site throughout the year,

others prefer to wander, a few moving as

far as the North Norfolk coast.

nesTs as well as neTs

16% of BTO staff also contribute to NRS.

Reedbed species are the staple of Dave’s

Cranwich project, with Reed Warblers the

stars and Reed Bunting, Moorhen and

Coot the supporting cast. More challenging

is Niall Burton’s long-term volunteer study

on Tree Pipit, one of the nation’s wariest

species at the nest, a particular issue given

the absence of cover for the observer

on the birds’ favoured clear-fell habitat.

Not to be outdone, Ian Henderson and

Greg Conway scour the same patches for

Nightjar nests, a barely perceptible scrape

at which activity is limited to the hours

of darkness! All nestlings found as part

of these projects are ringed, making any

re-encounter particularly valuable as their

exact age and origin are known.

a year-rOund pursuiT

Fieldwork doesn’t end with the summer,

either. Greg, Allison, lee and Graham

Austin are all involved with projects

exploring annual variation in moult

behaviour, primarily of finches, which

necessitate catching birds in autumn and

winter between Thetford and Brandon;

exchange of birds between their sites also

provides information on foraging ranges

and strategies.

Things are about to get busy and

our demographic volunteers are on

tenterhooks. Will bird numbers be up

after a productive breeding season? Will

this cold snap delay breeding? We look

forward to comparing notes over the

coming months!


LifecycLe

1. Reed WaRbleR is the most commonly encountered species across breckland CeS sites. at Cranwich, birds are also fitted with colour-rings to allow identification at the nest.

2. Ringing of SiSkinS in Thetford Forest throughout the year is providing valuable data on moult strategies.

3. Staff member niall burton monitors over 20 TRee PiPiT nests each year for his long-term study of this declining species.

3

2

Some of our BBS volunteers carry out their

BBS surveys for birds as normal and then

revisit the square a minimum of twice more

in July and August to record the butterflies

for the Wider Countryside Butterfly Survey

(WCBS).

Looking at the 2014 WCBS data from

BBS squares alone, Meadow Browns were

recorded in the highest number of squares –

253 of the 362 BBS squares surveyed – and

were also at the top of the table for having

the highest abundance. On the other end

of the scale, Adonis Blue, Brown Hairstreak

and Purple Emperor were recorded just once,

a rare treat for some BBS volunteers. There

is also the option of recording moths and

dragonflies during the WCBS visit: the most

widespread moth was the Six-spot Burnet

and, living up to its name, the Common

Darter dragonfly was seen on the highest

number of BBS squares.

But what has the WCBS carried out on

BBS squares told us about the birds and

the…butterflies? We often hear how ‘birds

are good indicators of

environmental change’;

the assumption is

that if well-monitored

species are increasing,

declining or stable, in

a given community

structure, other

unmonitored taxa will

be doing the same.

Past research suggests

this assumption is

strongest at the larger

scales. What about

when we look at

the finer scale? Cue

BBS and WCBS data!

Research using these data at a 1-km

square scale focused on the abundance

and community structure in birds and

butterflies on BBS squares, as well as

looking at this in relation to habitat and

latitudinal data.

From this information, the following

community measures can be assessed:

Species richness – total number of

species recorded in each visit;

Evenness – how different the abundances

of species within a community are from

one another. Evenness is highest when

a community is not dominated by a few,

highly abundant species or when all

species have an equal abundance;

Diversity – the function of both species

richness and evenness;

Specialisation – separating the

generalist species from the specialists.

Generalists can thrive in a wider range of

conditions or have a more varied diet than

specialists who require a more specific

habitat or food source.

At a fine scale, bird and butterfly

richness, diversity and specialisation

displayed the same trends. In these cases

the assumption that if well-monitored

species are increasing, declining or stable,


Working in partnerships

Since 2009, BTO, Centre for Ecology and Hydrology (CEH) and Butterfly Conservation (BC) have been working in partnership to monitor butterfly species across the UK. In 2014, 700 volunteers contributed to the survey, covering 831 randomly allocated 1-km squares. Of these squares, 44% were surveyed by BBS volunteers on BBS squares. BBS Organiser Sarah Harris says “Thank you!” and updates us on recent results.

the butterflies and

1

2

in a given community structure, other

unmonitored taxa will be doing the

same does apply. At a large scale,

latitude and habitat type did affect the

community measures but, for richness

and diversity, the relationship between

birds and butterflies remained strong.

The assumption that population trends of

well-monitored species will be reflected in

other taxa is supported for common and

widespread species but not for rare and

specialised ones. Conservation responses

for priority species are, therefore, unlikely

to benefit other species of conservation

concern, unless their declines have

common causes.

This study suggests applying this

principle at a finer scale to assist with

understanding the drivers of biodiversity

change, informing landowners and

conservation at individual sites.

Finally, thank you to all the fantastic

BBS Regional Organisers who manage

the survey locally and to the BBS

volunteers themselves. To find out more

about the BBS or adding the Wider

Countryside Butterfly Survey to your BBS

square, please visit www.bto.org/bbs, or

contact us at [email protected].


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BTO Registered Charity no. 216652 (England & Wales) no. SC039193 (Scotland). Butterfly Conservation Registered Charity no. 254937 (England & Wales) no. SC039268 (Scotland)

With a single payment to www.bto.org/birdsandbutterflies

or by calling 01842 750050 you will receive TWO memberships for the remainder of the year with all the

benefits each offers

Butterfly ConservationAND

BTO membershipfor just £30

JOIN 2-for-1

Offer available for new members of each organi-

sation only and closes on 31 May 2015. After 31 December

2015 you will be asked independently by both charities to renew although there is no obligation to do so.

In celebration of our work together:

Butterfly Conservation_Vol_ad.indd 1 03/03/2015 14:30:03

the butterflies and the birds

1. Meadow Brown This widespread and common butterfly topped the list of most frequently enountered species during wCBS surveys.

2. Swallowtail is a scarce and localised species in england, but occurred on one wCBS square. Unfortunately, the number of squares countrywide was still not high enough to pick up the influx of european Swallowtails on the south coast.

3. BBS VolUnteer taking on a wCBS square on your BBS square is a possibility, and 360 BBS surveyors chose to make return summer visits to their squares for this reason.

3

BTO Registered Charity no. 216652 (England & Wales) no. SC039193 (Scotland). Butterfly Conservation Registered Charity no. 254937 (England & Wales) no. SC039268 (Scotland)

With a single payment to www.bto.org/birdsandbutterflies

or by calling 01842 750050 you will receive TWO memberships for the remainder of the year with all the

benefits each offers

Butterfly ConservationAND

BTO membershipfor just £30

JOIN 2-for-1

Offer available for new members of each

organisation only and closes on 31 May 2015. After 31 December

2015 you will be asked independently by both charities to renew although there is no obligation to do so.

In celebration of our work together:

Butterfly Conservation_Vol_ad.indd 1 24/03/2015 14:59:44


In the 1930s only a few dozen people made

annual counts but the Heronries Census has

grown in popularity and now covers at least

60% of all UK heronries each year. Except

for the periodic ‘Heronries Surveys’, in which

special efforts were made to count heronries

nationwide, the survey kept a relatively low

profile throughout its early history – operating

mainly in England and Wales and receiving

data from relatively few counters, marshalled

for many years by expert volunteers.

BTO resumed allocating staff time to it in the

early 1990s and the Heronries Census emerged

as a full member of the BTO’s family of annual

monitoring surveys, organised through our

regional network. Growing volunteer support,

especially in Northern Ireland and Scotland, now

enables monitoring of Grey Heron populations

not just for the UK but also for the three British

countries separately, with ever-greater precision.

In parallel, extraordinary avian

developments put paid to the original

concept of the Heronries Census as a single-

species survey: it’s hard to contemplate that

Little Egrets were UK rarities until the 1980s

and unrecorded as breeders until 1996!

Since then they have become widespread

residents with a rapidly growing population.

Most joined in with existing colonies of Grey

Herons and have been reported by Heronries

Census counters. Spoonbill, Cattle Egret and

feral Night-herons have also nested among

Grey Herons and been counted for the

survey and around 10% of inland Cormorant

colonies are at sites also occupied by Grey

Herons. Coverage of all these colonial

Colonial Waterbirds

When observers for the first national survey of heronries posted their nest counts to Max Nicholson back in 1928 they could hardly have imagined that the survey would become an annual one and, nearly ninety years later, be entering another exciting new phase. John Marchant reports.

HErONrIES CENSUS GOES ONLINE

FIG 1. number of heronries counted. Coverage of UK heronries has increased greatly, boosted by periodic ‘Heronries surveys’, in which special efforts were made to count heronries nationwide.

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Colonial Waterbirds

waterbirds has become integral to the

survey’s role. Should ibises start to nest, they

would be covered by the Heronries Census,

but bitterns, Purple Heron and Great White

Egret, that mostly nest singly, are not.

Online data input and data access, long

familiar to supporters of our better-funded

surveys, has however not been available

for the Heronries Census. We are happy to

announce that, thanks to a generous legacy,

in 2015 the Heronries Census joins the BTO’s

array of online options.

MOdellIng HC daTa

Despite the expertise of our Information

Systems department in this area, designing a

database for an online Heronries Census has

presented a number of new challenges. There

are several reasons why approaches needed

to differ from our other online surveys.

Unlike all our previous online surveys,

the Heronries Census’s primary data –

counts of nests by colony and season – do

not relate to any particular date and time,

but are the product of data collection

across a whole breeding season. Sites are

chosen not randomly (as in BBS) nor by

observers (WeBS, BirdTrack) but by the birds

themselves. Especially in forestry, nesting

areas can shift over time, while remaining

recognisably the same colony. Outrageously, it

is still the case that some of the nesting sites

herons choose are vulnerable to persecution:

access to lists of heronry locations therefore

needs to be restricted. On the other hand,

we wish to open the survey more widely

to members of the public, who might have

access to land holding heronries as yet

unknown to the survey or could provide

valuable help with the early reporting of newly

established heronries.

These difficulties have been overcome

by introducing features new to BTO online

survey design, such as a more versatile

mapping tool and a new way for regional

Organisers to allocate sites. While visit

observations are entered against a date and

time, as in other surveys, the key value for

population monitoring – the ‘year’s best

estimate’ (YBE) – is recorded independently

against the season as a whole. The YBE

defaults to the year’s highest (or only) count

or estimate of apparently occupied nests but

the observer can override this, for example

if different nests in the colony had been

counted on different days. The survey’s

regional Organisers will verify or query dated

counts and can adjust each species’ YBE, for

example where additional observers have

supplied data for the same site. YBE requires

explicit data entries of zero, which are not

recorded for other BTO online surveys.

HerOnrIes OnlIne

The pages for the online survey are not fully

realised as I write but are due for launch in April.

Some previews are presented above.

The 2015 Heronries Census season has

started as normal, with regional Organisers

distributing cards to observers. Counts can

be returned in any format but we are hoping

for a strong take-up of the online system.

Data that reach us in the post or by email

will be input online. There is no intention to

phase out the cards – of which a new batch

has just been printed!

BrOadenIng THe sCOpe

There is much overlap between survey

requirements for herons and for other

birds that nest in colonies. For this reason,

the Heronries Census, with its range of

‘heronry’ species, is presented online as

the first and currently only module under

a new, exploratory concept – the Colonial

Birds recording Scheme. Thus, where

BTO can find the necessary resources, the

field is open to add new modules under

this umbrella over the years ahead where

observers can enter counts and YBE-style

data for apparently occupied nests of other

colonial birds such as rooks, martins, and

seabirds, at home or even abroad.

After exceptional periods of incubation

and growth, the fledgling Heronries Census

is starting to take flight!

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FIG 2. data are entered for each visit separately, along with the ‘year’s best estimate’ (Ybe) of apparently occupied nests of each of the species.

FIG 3. observers are encouraged to record the location and extent of colonies at fine scale. They can provide one or more editable polygons that relate to a particular year.

This year’s heron nesting season is already well under way. Soon, the Heronries Census will be receiving its first online submissions.

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BTO Volunteer 2015.indd 1 12/03/2015 16:48

volunteer magazine 2015

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