British Birds April 2010
The April issue of British Birds is now out and contains the following:
Great Blue Heron on Scilly – new to Britain
Ashley Fisher describes finding a first-winter Great Blue Heron on St Mary’s, Scilly, on 7th December 2007. It arrived during a period of sustained westerly winds that extended across the North Atlantic. The age of the bird, and the timing and circumstances of its discovery all point to this being a wild bird that arrived without the benefit of ship-assistance, and it has been accepted onto Category A of the British List.
Using stable isotopes to investigate the provenance of an Eagle Owl found in Norfolk
A stable isotope analysis of feathers from an Eagle Owl found in Norfolk in November 2006 is described in this paper by Andrew Kelly, Kevin Leighton and Jason Newton. The juvenile primaries and secondaries had a consistently low δ2H signature, while second-generation remiges, and body feathers revealed higher values. The pattern corresponds with the known moult patterns of Eagle Owls and suggests that the two generations of feathers were grown in different geographical regions. Although there are a number of alternative explanations for the findings, it seems most likely that it was reared somewhere with low local δ2H precipitation values. An origin in Scandinavia, north-continental Europe or mid-continental Russia is possible, but the possibility that the bird was reared in northern Britain, either in the wild or in captivity, could not be ruled out.
The breeding population of Northern Wheatears at Clee Hill, Shropshire, 1998–2008
The breeding population of Northern Wheatears at Clee Hill has been monitored since 1998 as part of the BTO Retrapping Adults for Survival project. Aspects of breeding biology, including laying dates, clutch size and brood size are presented by author Dave Fulton, together with estimates of the return rate of adult birds. There is some evidence that the local population may be declining, with 2009 being a particularly poor year; this may reflect a combination of the national population trend and perhaps deterioration in the habitat for Wheatears in the study area.
The decline of the Ring Ouzel in Britain
The Ring Ouzel is a Red-listed, UK Biodiversity Action Plan priority species in Britain because of steep declines in breeding numbers over the past 25 years. Innes Sim and his co-authors present data from several monitoring projects, from across much of the species’ British range, which show that widespread declines continue. Recent studies aimed at understanding these declines are reviewed, and suggest that low first-year, and possibly adult, survival may be the main demographic mechanism driving the decline. The research priorities are now to identify the factors affecting survival, determine where these factors are operating, and find management solutions.
Topics covered include Eskimo Curlews, more on the status of the Eagle Owl in Britain, and the definition and naming of the malar stripe.
Topics covered include an apparent nesting association between Northern Goshawks and Firecrests, a Common Kestrel attempting to predate Hobby chicks at the nest, the relationship between nesting Grey Herons and Common Ravens, and methods of monitoring Hawfinches.
Reviews, news & comment and a summary of recent reports complete the issue.
For more details, and to see download a recent issue of the magazine, visit www.britishbirds.co.uk