The oldest known blue tit survived an amazing 21 years. Robins often choose unusual nest sites – kettles, coat pockets and even the skeleton of a dead cat have been known. House sparrows make an untidy nest in eaves but very neat in hedges. They are sociable birds and prefer to nest in colonie.s A woodpigeon's nest is very flimsy and the eggs can sometimes be seen from below. Blackbirds will sometimes steal the snail from the song thrush once the shell is off. There are still between six and seven million pairs of house sparrows in Britain. In the 1970s, there were 12 million pairs. A great tit’s beak changes shape (very slightly) over the year as food changes from insects to nuts and seeds. A male starling sometimes has several females, and it is not uncommon for females to dump their eggs in another starling’s nest. A group of house sparrows is called a host or a tribe. A blue tit weights the same as a pound coin. The starling mainly eats spiders, slugs, caterpillars and other invertebrates. It probes for the larvae of craneflies, leaving holes in grassy areas. A pair of robins weigh roughly the same as one size 4 chicken egg. Starlings form large roosts in the evening. Some roosts attract thousands of birds and you can often see them performing aerial manoeuvres. Blue tit flocks travel amongst gardens in winter with as many as 200 individuals visiting a single garden in one day. The oldest wild blackbird survived over 20 years. Not all birds are expert nest builders – sometimes collared doves find their chicks fall through their flimsy nests. The male chaffinch’s fresh plumage in autumn gradually wears away to show bright spring colours. The great tit times its breeding around caterpillar availability – it may catch 10,000 in a season. Robins love cheese, butter and mealworms. When disturbed, woodpigeons clatter noisily out of trees and bushes. In its aerial territorial display, it flies up steeply, then claps its wings together above its back with a sharp slap before gliding down steeply. Although quite sociable, greenfinches squabble among themselves and sometimes with other birds at the bird table. Collared doves are very productive. They breed February–October and will often attempt four or five broods with one pair being known to have tried nine times. | 
