The December issue of British Birds is now out and contains the following:
What makes a successful alien? Dealing with the problems of non-native wildfowl
This is a thought-provoking paper by Tony Fox, originally presented as the 58th Bernard Tucker Memorial Lecture in November 2008. Humans have been introducing species outside their native ranges as a source of food for thousands of years, but introductions of wildfowl have increased dramatically since the 1700s. The most dramatic consequence of this has been the extinction of endemic forms as a result of hybridisation, although competition between alien and native forms may also contribute to species loss. Tony argues that the potential cost of greater environmental and economic damage, species extinction, and threats to the genetic and species diversity of native faunas means that we must do all we can to stop the deliberate or accidental introduction of species outside their natural range. International legislation to ensure this is remarkably good, but domestic law is generally weak, as is the political will to enforce such regulations. The case of Ruddy Duck in Europe will show whether control of a problem taxon can be achieved and underlines the financial consequences of dealing with introduced aliens.
Progress of the Ruddy Duck eradication programme
Following on in the alien wildfowl theme, Iain Henderson presents a review of the progress of the Ruddy Duck cull. The Ruddy Duck became established in the UK in the 1960s following escapes and releases; during the 1970s and 1980s it spread throughout the UK and was seen with increasing frequency in mainland Europe. Hybridisation with the Endangered White-headed Duck O. leucocephala was first recorded in Spain in 1991, and this is now regarded as the greatest threat to the long-term survival of the latter species. A programme aiming to protect the White-headed Duck by eradicating Ruddy Ducks from the UK began in 2005. Over 6,200 Ruddy Ducks have been culled at over 110 sites across England, Scotland and Wales under this programme, and data suggest that by winter 2008/09 the UK population had been reduced by almost 90%.
Britain’s first Baikal Teal
Evidence supporting the natural vagrancy of a Baikal Teal shot in Denmark in November 2005 prompted BOURC to review the British records of this species, and here Andrew Harrop and Bob McGowan present the results. A stable-hydrogen isotope analysis (see below) of feathers from the specimen of a Baikal Teal shot at Tillingham, Essex, in January 1906 suggested that the bird had not been hatched in western Europe, and this record was duly accepted by BOURC as the first for Britain. Ten subsequent British records were examined; of these, a first-winter male at Minsmere, Suffolk, in November–December 2001, was placed in Category A of the British List.
Stable-hydrogen isotope analyses suggest natural vagrancy of Baikal Teal to Britain
Steve Votier and colleagues present the findings of their analysis of the stable-hydrogen isotope signatures of feathers from the Essex Baikal Teal (see above), which reveal marked differences between juvenile feathers, grown on the breeding grounds, and post-juvenile feathers, grown on the wintering grounds. The natal-area signatures were consistent with a Siberian origin and the wintering-area signatures were consistent with a west European origin. The most parsimonious explanation of these findings is that the Essex bird originated within the normal breeding range of Baikal Teal and that its occurrence in Britain was the result of natural vagrancy.
BTO research update
Topics covered this month include a variety of interesting findings from late 2009 from the BTO Ringing Scheme (including movements of Glossy Ibises, a Kittiwake wreck in the Pyrenees and a bumper year for Cetti’s Warblers) and, from the WeBS unit, further evidence of shifts in Britain’s wintering waterbird distributions.
Reviews, news & comment and (another) bumper 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