BTO: Should I stay or should I go?

Goldfinch by Jill Pakenham/BTO ANL-140209-150521001
Goldfinch by Jill Pakenham/BTO ANL-140209-150521001
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It is at this time of the year that many garden feeding stations go a bit quiet. The abundance of hedgerow fruit and woodland seed provides feeding opportunities elsewhere for our finches, thrushes and other familiar birds, leaving hanging feeders full of seed little used.

Those birds that do appear, however, catch the eye and none more so than the goldfinch, a species that has greatly increased its use of gardens over recent years.

The goldfinches visiting Suffolk gardens at the moment will include some individuals that will move further south later in the year. Although most of our breeding goldfinches will remain throughout the year, a proportion moves south to winter in France and Spain. This pattern of movement, where some birds stay and others go, is known as partial migration. Individual birds will make a decision on whether or not to migrate, a decision influenced by the amount of food available and their chances of gaining access to it. This means that it is the younger and less competitive birds that tend to migrate, while older more socially dominant birds remain here. It should still be possible to identify young birds among the small flocks of goldfinches currently visiting feeding stations. Many of these youngsters will have yet to moult their juvenile body plumage through into adult patterning and can be recognised by the absence of the red, white and black head markings. The family parties will make use of seed mixes and, in particular, sunflower hearts and nyger seed, the latter a fine black, crescent-shaped seed that has to be provided within a specially designed feeder because it is so small. The fine bill of the goldfinch enables it to handle smaller seeds, like nyger, a trait that stems from the types of seeds taken in the wild. The goldfinch is the only finch to be able to extract the seeds from teasel, although it is only the males – with their longer bills – that can do this with ease.

The increasing use of gardens by goldfinches is something that has been charted by the BTO’s weekly Garden BirdWatch scheme, a ‘citizen science’ project that brings together many thousands of garden birdwatchers to collect the information needed to follow the changing fortunes of our garden birds. This dedicated army of volunteers has been watching Suffolk gardens since 1995, sending in their weekly observations, which are then analysed by researchers at the Thetford-based British Trust for Ornithology (BTO). Participants receive feedback on the wider patterns of garden use made by goldfinches and other birds (plus mammals, butterflies, reptiles, amphibians, bumblebees and dragonflies) through a quarterly magazine.

A free copy of the magazine, plus information on feeding garden birds is available from the BTO Garden BirdWatch Team (BTO, The Nunnery, Thetford, IP24 2PU or email gbw@bto.org with your address).