Blue Tit Ivor Verhaar CC

There’s a blue tit at my kitchen window, determined to get in. It repeatedly stabs at the glass, jumping up and down and flapping furiously. At first I thought it might be catching tiny spiders or insects, but it is so persistent that I think there can be none there now; that’s if there were any in the first place.

I can only imagine it sees a rival in its reflection. Tits are surprisingly aggressive birds, as anyone who has handled one will testify. But why does this bird take such an interest in its reflection, when other birds don’t?

One guess might be that my window happens to fall within its territory. But I’ve watched carefully and this same bird also takes umbrage at reflections in the mirrors of cars parked some thirty yards away. Has it a large territory, or does it go looking for trouble? There are lots of blue tits here: they don’t seem bothered.

Birds and other creatures that look alike and have strong species related behaviours are sometimes surprisingly individualistic. But why that should be so is a more difficult question to answer.

I’m watching a murmeration of starlings. Hundreds, maybe thousands of birds swirl and dance in the air together making up what looks like one composite organism. Suddenly one breaks free and heads off in another direction. Why? What caused that particular bird to do that?

Individuality in most species can be a dangerous thing. There are good reasons why things remain true to type in their behaviours, particularly if they are vulnerable to attack from predators. But sometimes there are exceptions. Individual variations in behaviour, suggestive of temperament, can be observed in a very wide range of species. That primates and top of the chain predators should display differences might not be surprising, and any pet owner will tell you that his or her dog / cat / budgie/ has a personality unique to itself. Is this just sentimental anthropomorphism, or is there more individual variation amongst animals and birds than we think?

One of the reasons there is little evidence for individual variation is that experimental studies are constructed to eliminate such niggling variations that might obscure the thing being searched for. Such experiments often include large numbers of individuals precisely to minimise corruption of data by small or otherwise irrelevant variations. And what applies to experiments also applies to everyday observations: we only see what we look for. But close acquaintance with individuals in any species will confirm that such variations do occur, even among earthworms and fruit flies.

It seems that a propensity to individual variations is linked to DNA programming, but the outcome of that is heavily influenced by environmental factors, including not only the external physical or social environmental ones but also internal factors that start to impact in the womb.  As the saying goes: “genes load the gun, but environment pulls the trigger.”

Which doesn’t explain why my particular little blue tit is so obsessed with its own reflection, while others are not so inclined. Maybe it’s has always been a bit on the stroppy side, even as a chick. Only its mother knows. But if it is unique, it’s not alone.

blue tit at window - Crackers 93 CC

Image 1 Ivo Verhaar, Flickr Creative Commons

Image 2 Crackers 93, Flickr Creative commons

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