Genetically encoded robins

I HAVE been adopted by a wild bird. Every time I go outside it appears within minutes and follows me around. It gets very close. It’s a rather odd sensation. The bird is an immature robin, still in its speckled baby plumage.

Robins have a habit of becoming tame but, up until now, I had assumed this was something they learned. I thought they watched people and noticed they were sometimes a source of food, unearthing worms while they dug in the garden, for example, and they posed no real threat. But my new friend is far too young to have learned anything like this so I have to assume that its tameness is genetically inherited.

Sometimes young birds can ‘imprint’ on humans and treat them as if they were their parents. This mostly seems to happen with water birds. The ethologist Konrad Lorenz described it in geese and it once happened to me with a water hen chick. But I don’t believe that the odd behaviour of my baby robin can be adequately explained by imprinting. I think something else is going on.

Robins are found over most of Europe, along with a bit of north Africa and western Siberia. Everywhere except in Britain and Ireland they are shy forest birds that avoid human contact. Irish and British robins are described by some experts as a separate sub-species. This is not because of any differences in behaviour but because of some minor differences in plumage colour. But their behaviour certainly is different because they are one of our tamest wild birds and seem to actively seek out the company of people.

The explanation for this seems to be that the robin has evolved in an ecological niche where it makes a living following large forest animals around and feeding on the invertebrates they unearth. It concentrates in particular on groups of European wild pigs. Wild pigs feed by rooting through the leaf mould on the woodland floor, using their snouts and, to a lesser extent, their front hooves. They are extremely efficient pieces of earth-moving equipment, leaving behind good robin food..

Wild pigs were exterminated in Britain and Ireland at some time in the Middle Ages, although they have re-established themselves in small numbers in recent years as farm escapes. Shortly after their extinction most of the wild woodland in both countries was felled. This presented a problem for robins. It appears they solved it by replacing the wild pigs with human gardeners, who are also quite efficient earth movers. There have been enough robin generations since then for the behaviour to become genetically encoded.