Wednesday, 3 February 2010

Damp days should bring Siskins

It is on just this sort of damp day that I would expect the first of the winter’s Siskins to put in an appearance on my bird feeders. These small, streaky, green finches are a feature of late winter, arriving to feed alongside the larger and more robust Greenfinches, Great Tits and Chaffinches on sunflower hearts and mixed seed. The Siskins are around in the forest, though not in particularly large numbers this year and I wonder if it might turn out to be a fairly quiet winter for them.

Siskins breed in conifer forests across much of Northern Europe and while UK breeding populations are largely restricted to the north of the country, they do breed in Thetford Forest and similar woodland across parts of southern Britain, taking advantage of the maturing commercial plantations. During winter the birds may range more widely and they turn up as winter visitors to gardens across much of south-eastern England. Here, in the Brecks, I know of people who have them visit throughout the year, the adult birds arriving in summer with newly fledged young in tow. Despite this, they remain a predominantly winter visitor to my own garden.

The productivity of these small finches, and indeed the degree to which they use gardens, is linked to the size of the seed crop produced by the dark ranks of conifers. In years when the seed crop is large, the Siskins tend to enjoy a productive breeding season but, by the same token, when the seed crop is poor, breeding success is reduced. Food availability determines the extent to which Siskins turn to handouts provided in gardens. In years of a good seed crop the birds can remain within their favoured forest habitats and do not need to venture elsewhere. In such years, not only will our British birds remain in the forests but also the winter immigrants that we receive from continental Europe will stay overseas.

Even when the birds are here, the use of garden feeding stations will be influenced by the weather. On damp days the conifer cones remain clamped shut and the seed on which the Siskins feed remains locked away. It is only on dry days, when the cones open to disperse their seed, that the Siskins have access to their favoured food. Of course, it is not just conifer seeds that these birds take and if they cannot access these seeds you may find them feeding on riverside Alders. Only when such alternative resources have run out will the Siskins arrive in gardens in any numbers. While it is a shame not to have Siskins on my feeders it is a sign that things are well elsewhere.

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