Us and them
Every gull species has typical characteristics which distinguish it from others– its call, behaviour, colour and form. These characteristics can be very slight and specific, for example the colour of the eye or the coloured orbital ring around the eye.
Learned behaviour
The ability to recognize individuals of the same species is something that nestlings learn from contact with their parents. They are "imprinted" with the appearance of their own species.
Well-researched
Scientific studies have shown that chicks raised by a different gull species often perceive that species as their own. When they grow up and choose a mate, it is often of the imprinted species. However, precisely which details they learn to recognize is something that is still not clear.
Mother's breast
An animal's behaviour is often a mixture of inherited and learned elements, as in the case of the herring gull. The same applies to us human beings. To ride a bicycle is a skill that is learned with some difficulty. But to take milk from your mother's breast– who taught you that?
