Tuesday, 10 January 2006

Worrying decline of much-loved bird

The largest and most majestic of our breeding finches, the hawfinch, is a now an increasingly rare delight for the Norfolk birdwatcher. With its cinnamon and chestnut plumage, black bib and extremely stout beak, this wonderful bird is one of the real gems of the bird world. Unfortunately, its elusive and secretive nature, coupled with an alarming decline in breeding numbers, make this a difficult bird to see, especially during the breeding season. It is during the winter then, that it is well worth visiting one of the handful of sites which support small wintering flocks. Within Norfolk, Barnham Cross Common and Lynford Arboretum, both in the west of the county, are the most reliable sites. However, even here the birds can be difficult to see. 

During the winter months, the hawfinch feeds on the fruits and seeds of various trees, favouring those of hornbeam, field maple and cherry. The bird uses its stout bill and very well developed facial muscles to crush open cherry stones. The stone is held within the bill, balanced on four horny pads attached to the inside of the upper and lower mandibles, and the bird then applies a crushing pressure reported to be more than 1,000 times greater than its own body weight! This ability is reflected in the bird’s Latin name of ‘Coccothraustes’, which derives from two Greek words meaning ‘a kernal’ and ‘I break into pieces’. The power of the bill, coupled with an aggressive nature, is probably the reason behind the rather peculiar courtship display of this species. The display is highly ritualised and involves a large number of submissive gestures and a very cautious approach on the part of the male.

The Hawfinch has a very patchy distribution in Britain and the most important populations are now located outside of Norfolk. These populations have declined, possibly because of changes in the quality of favoured woodland habitats, increased competition for food and nest predation by introduced grey squirrels. During the 1970s and early 1980s large flocks would be fairly commonplace in winter but flocks in excess of 10 birds are now most unusual. This pattern can be seen in Norfolk. In the winter of 1974/75 a flock of some 183 birds was present at East Wretham but by 1986 very few birds were using the site. Numbers at the Lynford and Barnham Cross Common sites are also far smaller than they once were – both in single figures. For how much longer will we hang onto these wonderful birds? However, there is one piece of encouraging news. Following a tree planting campaign, numbers have been increasing on the Dutch polders. Perhaps the hawfinch may benefit from similar schemes here in East Anglia.

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