Willow Warbler
Phylloscopus trochilus
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Distribution Britain 2,602 (+0.6%) Ireland 927 (-1.4%)
Numbers breeding: Britain 2,300,000 Ireland 830,000 European status: 39,000,000 (8% in Britain and Ireland = 4=) British population trend: stable until recent declines (-23% CBC){-23%} How likely are you to record it? 2706 squares (60.3%) Ranked 16 [17] |
The Willow Warbler was considered, 100 years ago, to be the commonest warbler in northern England and over most of Scotland but the Whitethroat was more numerous in England. They were sparse in the west of Ireland and breeding was not proved on Orkney or the Western Isles and not suspected on Shetland. Now the birds have expanded to occupy extra areas in western Ireland and to breed on Orkney and the Western Isles — even, sometimes, on Shetland. Everything seemed to be going very well with a very steady CBC index until about ten years ago when there were bad losses which affected the southern British population but not those in the North. Detailed research indicates that these were due to poor adult survival and thus changes on migration or in Africa might have been to blame. More recently the five-year BBS index (1994-1998) logged a strong recovery of 25% so the problem may only be a short-term glitch. This is a species showing a significantly earlier first egg date and an increasing brood size — probably correlated with global warming. Looking quite good but are there clouds on the horizon still?
The following Bird On! sketch is available:
Willow Warbler
From
The
State of the Nations Birds
Copyright © 2000 by Chris Mead