Tarvin Community Woodland
The Greenfinch (Chloris chloris)
Click on the birdsong link to listen to the song of the Greenfinch in a separate tab while you read this article: Greenfinch song
A greenfinch will attract little attention if sitting quietly on a branch. However, the flash of yellow and green as it flies, together with its twittering, wheezing song, make this finch a truly colourful character. One of the larger, chunkier finches, it is similar in size and shape to a house sparrow, with a bill that is thick and conical and the colours of the two genders are almost identical – the male is mostly olive-green with a yellow patch on the wings and tail, while females are grey-green with rather less yellow. They feed largely on seeds, but will also take berries.
Greenfinches nest in small colonies in tall shrubs or trees and will choose open woods, hedges and large gardens. Their nests are typically bulky and are made of grass and twigs. They usually begin to breed in the second half of March, and continue until June, with fledging young still being around as late as early July. Incubation by the female lasts for 13-14 days, during which time the male feeds her at the nest. Once hatched, the chicks are covered with thick, long, greyish-white down and are fed on insect larvae by both adults during their first few days. As they get older their diet changes and they receive a frequently regurgitated yellowish paste made of seeds. They leave the nest after about 13 days but are still unable to fly. Fledging usually occurs between 16-18 days after hatching. In good seasons, the parents may manage to raise three broods, while two broods are quite common.
Greenfinch populations have been found to fluctuate greatly, with recent declines being linked to an outbreak of trichomonosis, a parasite-induced disease which prevents the birds from feeding properly. Pigeons and raptors were known to be susceptible to this illness, but, beginning in Great Britain in 2005, carcasses of dead European greenfinches and common chaffinches were found to be infected with the parasite. The spread of the disease is believed to have been aided by common chaffinches, as large numbers of the birds breed in northern Europe and winter in Great Britain, thereby introducing the parasite to the more-resident goldfinch population. However, it would appear that greenfinches are far more badly affected than are chaffinches, where only a relatively minor change in the population results, in contrast to the serious population decline in goldfinches.