friends or foes: facing the facts about american crows

Friends or Foes: Facing the Facts About American Crows

David P. CraigWillamette University - Department of Biology

Who knows

what this

is ?

The Rook (Corvus frugilegus)i.e. the food-gathering crow of Eurasia

Everybody has a crow story

Everybody has a crow story

Everybody has a crow story

Everybody has a crow story

‘Welcome to Science Whitewing” “I got him, John!” “How was your climb?”

Predator Recognition by Crows

Crow Call TypesCaw

Scold

Sociality and Relatively Large Brains May Enable Discrimination

Can You Tell the Difference Between Dick Cheney and a Caveman?

CheneyCaveman

CheneyCaveman

Can Crows Tell the Difference Between Dick Cheney and a Caveman?

Two Main Questions

1) Can wild American Crows learn to recognize individual people?

2) Does social learning take place?

What About Ordinary Faces?

Study Treatments

• Ten trials per site

• Nine treatments per trial– Negative mask– Five neutral masks– Negative mask + armband– Two neutral masks + armband

The dangerous face is always

recognized, and especially likely to attract a mob,but not perfectly.

Two Mask Trials

• One mask at a time

• Choice among masks

When forced to select the Dangerous from a Neutral Mask, when both were presented simultaneously, Crows accurately

discriminated among all the ordinary masks.

Two Main Questions

1) Can American Crows learn to recognize individual people?

2) Does social learning take place?

Acquisition of Information

• Individual “trial and error” Learning– Allows Flexibility,– But Dangerous

• Social Learning– Flexible– Reduced Cost

Three Opportunities for Observational Learning

1) At time of capture2) Associating with

crows who were captured when they encounter the trapping mask at a later date

3) Young of crows who had been captured

Spread in the Geographical

Extent of Scolding the Extraordinary

Face over 2.8 Years

Urban Site (B.) shows a result

similar to the pilot study but not

elsewhere (A.)

Downtown urban site has similar density and unpredictable identity of humans as does the pilot campus site

Dangerous mask downtown was bald man, most similar to extraordinary face from campus

Individuals with the Direct Experience of Being Captured Learned to Discriminate Faces More Accurately Than Those

Only Observing Capture or Subsequent Scolding of Captors

Vertical Learning• We put a radio tag on young

crows (without ourselves wearing a mask) whose parents scold the dangerous mask

• While under parental care, the young observe their parents scold the dangerous mask

• Independent of parental care, the young crow scolds the dangerous mask

Crow Paradox

Face Recognition

Halloween Mask Sales on AmazonPredicted Election

San Onofre aka

St Onuphrius by the Spanish painter,

Francisco Collantes

(1599-1656)

 Museo del Prado

CULT of CORAX