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Birdchick Blog: New Mind Games To Play With Starlings

Tuesday, April 29, 2008

New Mind Games To Play With Starlings

From The Telegraph:

Starlings can tell if you are watching them, according to a study that has shown for the first time that starlings respond to a human's gaze.

Starlings will keep away from their food dish if a human is looking at it. However, if the person is just as close, but their eyes are turned away, the birds resumed feeding earlier and consumed more food overall, according to experiments by Julia Carter and colleagues at the University of Bristol, reported today in the Proceedings of the Royal Society Biological Sciences.

Could this be exploited to make a better scarecrow? "Starlings do seem to have a reasonably strong aversion to eyes, even to artificial eyes, but these birds are also very quick learners," she says.

"Previous studies have shown that starlings will learn within a matter of hours to ignore even relatively elaborate bird scarers - these devices never do what a real predator would, they don't actually chase the birds or present any other signs of danger, so the birds quickly learn to ignore them."

This fear of being observed directly may be hard wired into bird brains, since predators tend to look at their prey when they attack, so direct eye-gaze can predict imminent danger. Equally, it might be a sign that starlings are doing something smarter than that, by taking into account the view of another, not just another bird but another species.

Carter says:"It is not yet clear what this means for the intelligence of starlings, they are certainly far more observant and sensitive to human facial cues that we might have imagined - what we find is responses to really very subtle differences in a human's eye-gaze, even though there are far more conspicuous and salient cues that don't change in the experiment: the close proximity of the person, and their body and face orientation."

"The possibility that the starlings can "read the intention of another species" is certainly an intriguing one, and is indeed an interesting possibility, though there are likely alternatives to consider," she says.

"The simplest explanation might be that these birds are responding at an innate instinctive level: circular eye-like patterns are thought to be rather conspicuous to vertebrates like starlings, so a human who is staring directly at the starling is likely to attract the bird's attention (because the direct eye-gaze presents a completely visible circular pattern) more so than the averted eye-gaze (which presents an angled view, and therefore a less circular pattern)."

Another likely possibility is that the starlings have learned to fear a direct look. "If a starling is ever chased or captured in the wild or in captivity, the event is preceded by the captor looking directly at the bird.

"A starling is never chased if it is not looked at first, so a predictive relationship can be learned - looking leads to a risk of capture. The final possibility is that the starling can recognise that the human is looking at it, and infer the likelihood that they will consequently be chased."

But, she says, "It is notoriously difficult to get inside the black box of an animal's brain in order to establish, for example, whether they can appreciate another's visual perspective or even whether they have a 'theory of mind'.

The reason that they benefit from being sensitive to a human gaze is down to peer pressure. Wild starlings are highly social and will quickly join others at a productive foraging patch. This leads to tough competition for food so an individual starling that assesses a relatively low predation risk, and responds by returning more quickly to a foraging patch (as in this study), will gain valuable feeding time before others join the patch.

"By responding to these subtle eye-gaze cues, starlings would gain a competitive advantage over individuals that are not so observant. This work highlights the importance of considering even very subtle signals that might be used in an animal's decision-making process."

Responses to obvious indicators of risk - a predator looming overhead or the fleeing of other animals - are well documented, but Carter argued that a predator's head and eye-gaze direction are also useful indicators of risk, even though subtle, since many predators orient their head and eyes towards their prey as they attack.

Carter did the study with Nicholas Lyons, Hannah Cole, and Arthur Goldsmith.


Blogger Scott Taylor said...

The mimicry of starlings still blows me away. I've probably heard more hawk and gull calls from a group of starlings than I have from the real deal. I go back and forth between thinking they do it to scare off other potential competition in the area, or to just taunt other birds (and birdwatchers). Or maybe they do it simply because they can. Thats often my motivation.

4/30/2008 1:41 AM  
Anonymous WA Twitchgirl said...

When living in the Netherlands, the starlings nesting in my roof always told me when the migratory waders had arrived in the fields just outside the town. The starlings foraged in the paddocks alongside the nesting and displaying waders and brought their calls home in the evening.
Starlings are like tourists, picking up sound souvenirs wherever they go. Wonder how many foreign bird calls I heard that I could not identify while listening to them in my bed in the morning. Ah.. so long ago.

4/30/2008 3:45 AM  
Blogger Aunt "B's" Backyard said...

I am going to look like a 'birdbrain' outside staring the starlings down! hehe
Lots of info in this post, wonderful!

4/30/2008 6:19 AM  
Blogger Robin said...

Awesome photos!! Thanks for the article too--starlings rock!

4/30/2008 6:38 AM  
Blogger AKA Bird Nerd said...

If I fix my eyes on my African Gray, she'll come over to me. When I first got her (many years ago) I was careful about staring her in the eyes because it made her uncomfortable. It goes beyond that - she reacts to my facial expression.

4/30/2008 7:41 AM  
Anonymous Els said...

When my canary (housebird) sings and I look at him directly, he stops inmediately. When I look 10 cm. besides him, he continues.

They are allowed to fly free in my room and sometimes sit in the open entrance looking out. When I approach backwards I can easily shut the little door. When I approach in the normal way and they aren't ready to be locked in, he'll fly out.

There's a lot going on in those little brains... ;)

4/30/2008 10:27 AM  
Blogger Stacy said...

This may sound lame; but I've always thought Starlings were a nuisance. I thought they weren't indigenous and they have displaced other indigenous species?

4/30/2008 10:33 PM  
Blogger Larry said...

I'm sure there's that one or more of the scientifc explanations given probably has something to do with their reactions when being watched. However, when I listen to a large flock of starlings vocalizing I can't help but get the feeling that there is some intelligent communication going on there.

5/07/2008 7:46 PM  

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