In human society we are often encouraged to be different, unique, to follow our own path or to stand out from the crowd. However, is the same true for pigeons?

I have been lucky enough to have been contacted by researchers interested in this topic, which got me thinking. They brought to my attention a study investigating goshawk (Accipiter gentilis) hunting habits (see the study here: www.cell.com/current-biology/abstract/S0960-9822(12)00315-6). It was found that rare or unusual phenotypes were chosen as prey items above and beyond the more common phenotypes in the flocks they were hunting.

You would imagine that such hunting pressure would select against the rare phenotype causing flocks to become uniform. However, negative assortative mating in pigeons means rare phenotypes are highly sought after as mates, perpetuating the ‘rare’ phenotypes. Is this the end of the matter? Is negative assortative mating sufficient to maintain plumage variation in face of hunting pressure?

Anthropogenic influences may also have an effect. For example, when counting pigeons earlier in the year, I encountered a man abandoning a fledgling captive bred white pigeon into a town flock. She was too young to survive on her own and so came home with me for hand rearing.

Given what is known about the oddity effect it would be unfair to release her and so she currently remains with me. But it does make you wonder how much of the gene pool consists of escaped/released individuals and how much is the result of negative assortative mating. Equally, it is known that melanic male pigeons have less gonadal regression and can breed for longer when they have access to sufficient food. Could white or red individuals have other unknown traits that help them prevail?

From what we know, being the odd one out for a feral pigeon is both a curse and a blessing. As an unusual phenotype an individual may find a mate more easily and (if male) may have more extra pair matings and therefore may have greater lifetime reproductive success. Given that unusual phenotypes are, just that, unusual, it is evident that selective pressure against such phenotypes must be strong.

It is clear there is still lots to be learned about these familiar birds. And as for the white pigeon, she is currently teaching me a lot about post juvenile moult by spreading her feathers all over my lounge. Here she is roosting on a clothes horse.

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