Specialist & Generalist

This is a treecreeper, Certhia familiaris, a tiny bird not much bigger than a wren which we've very rarely seen. This may in part be because their camouflage and mode of life, clinging to the trunks trees and moving up silently, make them difficult to spot. Yet we've seen two in two weeks, one of them in the holly tree close to our back yard.

They're real specialists, confining themselves to such bugs and other tiny creatures they can find hidden in the cracks and crannies in tree bark. They're specialists, and they seem to be very successful, though a bitterly cold winter, when water freezes in the bark, can be fairly disastrous for them.

By contrast, we have loads of one of the great generalists, the house sparrow, of which there is no shortage here in Golspie. They've quickly learnt to use the various feeders we've put into the back yard, muscling the tits off the peanut feeders and scrapping with each other and anything else that tries to displace them from the bird table.

Their adaptability has enabled them to live near humans and thus to spread well beyond their Eurasian home range, to North and South America, southern Africa and Australia.