Garden Bird of the Month – The Greenfinch
The Greenfinch is a familiar bird seen in both rural and urban gardens. The male is a dull olive-green colour with a yellowish breast, grey cheeks and distinctive yellow wing flashes. Females are duller with less yellow and juveniles are paler and streakier. Females and juveniles are often confused with female House Sparrows. The Greenfinch is a gregarious species which tends to nest in loose flocks, especially in conifers. It is, however, often aggressive towards its own kind and other birds at feeding stations. Once settled on a feeder, it will nibble away contentedly for ages. Having a thick bill, it can eat most types of seed and peanuts, but it favours black sunflower seeds and sunflower hearts.
Over the past few decades the Greenfinch has experienced a few peaks and troughs in its population. Research has shown that in the 1970’s and 1980’s the species declined but then dramatically increased during the 1990’s. Unfortunately, it is now in decline again and numbers have plummeted over the last ten years, mainly due to a parasitic disease called Trichomonosis.
It was in 2005 that people began reporting that Greenfinches were being found sick or dead. The disease is also found in other species such as pigeons, doves, House Sparrows and Chaffinches but Greenfinches seem particularly prone. The disease affects the upper digestive tract and causes lesions at the back of the throat. As they worsen, the throat becomes blocked and the bird is then unable to eat or drink, eventually dying of starvation or dehydration. To help prevent this disease from spreading, good standards of hygiene at bird tables, bird baths and feeders is essential.
Jean is a voluntary Ambassador for the British Trust for Ornithology’s (BTO) Garden BirdWatch scheme in Nottinghamshire. If you enjoy watching birds and other wildlife which visit your garden, Garden BirdWatch may be perfect for you. If you would like a free information pack about the scheme, contact Jean at firstname.lastname@example.org or visit www.bto.org/gbw