I have been reading 'The Life of the Robin' (4th edition) by David Lack (publ. Fontana New Naturalist) in an attempt to learn something about the robins (Erithacus rubecula) that live in my garden.
I see robins in my garden all year round and had always assumed they don't migrate. From reading Mr Lack's book however, I've discovered that although male (cock) robins very rarely migrate, remaining permanently with their terroitories, about three quarters of hen robins do. The book gives records of robins having travelled from southern Spain to northern Germany and, closer to home for me, a robin ringed in Berkshire (UK) being later recovered in Voorn, Holland.
One thing it surprised me to learn is that robin song is apparantly learnt and not instinctive; A robin chick raised by a nightingale will sing like a nightingale. Knowing this, I find it surprising that robins as a whole share a common song. Having every robin only learn its song from two others (its parents) would seem to me a guaranteed recipe for 'chinese whispers' i.e. for robin song to break-up into numerous very different local dialects. Or maybe it has? Can anyone comment on this?
I wrote here that life as a blackbird seemed pretty tough. I've discovered it is luxury compared to life as a robin! The annual mortality rate for robins is a massive 62% for adults and 72% for juveniles. The book lists causes of death including death by cats, drowning, starvation, hitting telegraph wires, other robins, stoats, weasels, rats, dogs, sparrowhawks, little owls, great grey shrikes and "hitting netting in fog". Remind me not to come back as a robin!
The famous feature of British robins is their relative tameness and status as 'the gardener's friend'. Certainly whenever I dig my garden I can be fairly guaranteed to have one accompany me, darting in to grab insects as I'm turning over the soil. I've heard the suggestion that this behaviour might have evolved through robins associating with wild boars as they rooted through leaf-litter in ancient forests. Apparantly however, robins on the European mainland do not share this characteristic, and instead are shy birds which avoid people. Why are things different here?
Other things I discovered from reading the book include:
That none other that Charles Darwin studied and wrote about robin song in his book The Descent of Man and Selection in relation to Sex (1871)
That there is a record of a robin making its nest on a wagon which later needed to be moved from Walton Heath to Worthing with the young still in it. The parent robin travelled with the nest for about a hunded miles each way, feeding the young en route.
I was particularly amused by the comment in the book :
"The robin uses his [life] for singing and fighting. The great crested grebe, on the other hand, was found by Julian Huxley to spend much of summer in courtship, and the cirl bunting, watched by L.S.V.Venables, seems to spend most of its spare time doing nothing in particular, a dull bird to watch"
Hooray for robins, boo for buntings!