Sunday, 24 February 2013

Are you looking at me?!

A large part of the Blackbird project involves re-sighting birds we have previously caught. On our most recent visit we noticed that the birds' behaviour to our attentions can be different to that compared to their behaviour toward other park users.

Even though a walker, cyclist, jogger or even dog walker would pass by a few metres from them, the birds would move away calmly with a few hops towards cover, re-emerging only a few seconds later. However,  on a few occassions when we focussed scopes or binoculars on them, despite being 10m or so away, the birds would move towards cover with much more urgency sometimes flying to the nearest hedge or up into a tree. Surely, being further away, we represent far less of a threat?
The answer may lay in the results of a recent study published in the journal Ethology. Clucas and colleagues looked at how American Crows (Corvus brachyrhynchos) varied the urgency of escape and flight intitiation distance to approaches by humans with varying degrees of eye contact and facial expression.

Although the facial expression (smiling or scowling, sadly they didn't test frustration) of an approaching human had no affect on the crows behaviour, the amount of eye contact did. Crows moved away sooner and with more urgency when the human was gazing directly at them compared to when they averted their gaze. Such a response may represent an adaptation to living in urban areas with the crows using this visual cue to gauge the intention of onlookers.

While other park users may pay little attention to the blackbirds, we are directly gazing at them when trying to read their ring numbers. Perhaps some of them perceive the lenses of our binoculars or scopes as eyes, exaggerating the "gaze affect"?

With a little fieldcraft and patience we did manage to re-sight A4, B6, B4, AB,  BK and BD, not to mention several unringed birds! A4 in particular seems completely oblivious to our attentions and at one point stopped in front of us before resuming feeding a few metres away.

Here's looking at you: Intially some blackbirds are wary when the binoculars
 are focused on them, while others carry on feeding as normal.

Clucas, B., Marzluff, J. M., Mackovjak, D., Palmquist, I. (2013), Do American Crows Pay Attention to Human Gaze and Facial Expressions?. Ethology. doi: 10.1111/eth.12064

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