British Birds February 2011
The February issue of British Birds is now out and contains the following:
Northern Gannets in the North Sea: foraging distribution and feeding techniques around the Bass Rock
Field observations around the largest Northern Gannet colony in the North Sea, the Bass Rock, showed that two-thirds of all Gannets foraged in areas with very low densities of other Gannets and more than 100 km from the colony. When one forager found prey, even distant Gannets responded by joining the finder to obtain a share of the bounty but feeding opportunities were typically exploited by small flocks. Intraspecific competition was thus less intense than it would have been nearer the colony. Searching and feeding tactics of Gannets, as well as foraging associations with other top predators, were different between sea areas. Low numbers of Gannets per flock occurred within inshore multi-species foraging associations, where Gannets hampered feeding opportunities for other seabirds (and themselves) by plunge-diving into compact schools of small prey fish. Larger flocks of competing Gannets formed in situations where an escape response in prey fish was absent (discards behind commercial trawlers) or weakened (fish schools herded by marine mammals). The association of Gannets with marine mammals was typically an offshore phenomenon, despite the abundance of cetaceans in inshore waters. Discards were a fairly unimportant source of food during the breeding season and natural feeding opportunities were widespread.
The probable breeding of Ferruginous Ducks in Avon
Andy Davis and Keith Vinicombe document the probable breeding of Ferruginous Ducks at Chew Valley Lake, Avon. In 2003 and 2004, nesting attempts probably took place, although no nest or young were observed and it was assumed that any attempts failed. In 2006, a juvenile male appeared in October. Although it could not be established that this bird had hatched at Chew, events suggest that it may well have done so and perhaps was raised by a foster parent (probably a Common Pochard).
The Sociable Lapwing in Europe
Records of the Sociable Lapwing in western and central Europe were analysed. Sightings in these areas reached 20–21 per year in 2003–05, the most recent years for which complete data were available for all countries in the study area, with records from France, Spain and Portugal amounting to one-third of the European total during 1996–2005. While most occurred in spring or autumn, records in the Iberian Peninsula were concentrated in the winter months. Spring movements appeared to be, on average, faster and to follow a more southerly route than those in autumn. Numbers reported were only slightly lower in spring than in autumn, suggesting that winter mortality rates may be low. In autumn, about 60% of birds that were aged were in juvenile/first-year plumage. The observed patterns, taking into account the numbers and distribution of observers and the species’ habitat preferences, support the hypothesis that small numbers of Sociable Lapwings may winter regularly in Iberia.
The BB/BTO Best Bird Book of the Year 2010
British Birds and the British Trust for Ornithology announce the winner of the Award for Best Bird Book of the Year: Living on the Edge: wetlands and birds in a changing Sahel, by Leo Zwarts, Rob G. Bijlsma, Jan van der Kamp and Eddy Wymenga (KNNV Publishing, 2009).
Notes in this issue include discussion and photographs of, among other things, female song in the Ring Ouzel, juvenile Common Coots feeding second-brood young and marks on the irides of Black Woodpeckers
As usual, a range of 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 our website at www.britishbirds.co.uk