Royal Society for the Protection of Birds

About: Royal Society for the Protection of Birds is a nonprofit organization based out in Sandy, United Kingdom. It is known for research contribution in the topics: Population & Biodiversity. The organization has 670 authors who have published 1425 publications receiving 88006 citations. The organization is also known as: RSPB & Plumage League.

Satellite tracking reveals the migration route and wintering area of the Middle East population of Critically Endangered northern bald ibis Geronticus eremita.

Abstract: Since its discovery in 2002 the small colony of northern bald ibis Geronticus eremita in the central Syrian desert remains at perilously low numbers, despite good productivity and some protection at their breeding grounds. The Syrian birds are migratory and return rates of young birds appear to have been poor but because the migration route and wintering sites were unknown little could be done to address any problems away from Syria. Satellite tracking of three adult birds in 2006-2007 has shown they migrate through Jordan, Saudi Arabia and Yemen to the central highlands of Ethiopia. The three tagged birds and one other adult were found at the wintering site but none of the nine younger birds that also left Syria were with them. At least four birds wintered elsewhere because they returned to the colony the following spring. The return migration followed the western shore of the Red Sea through Eritrea to Sudan before crossing the Red Sea into Saudi Arabia, then northwards to Syria. The adults appeared to be at low risk on the wintering site although we recommend protection. Threats along the migration route now need to be assessed and mitigated, and further effort made to determine the movements of subadults and young birds.

Foods of the Dartford warbler Sylvia undata on southern English heathland (Aves: Sylviidae)

Abstract: This paper describes the invertebrates of Callunetum and gorse on lowland heaths in Dorset and relates how these were exploited by the Dartford warbler Sylvia undata, a scarce bird of interest to nature conservation and one of the small number of wholly insectivorous resident passerines in Britain. Gorse had a denser invertebrate fauna than Callunetum and was used for feeding at a frequency out of proportion to its abundance. Diets of adult birds closely reflected the taxonomic composition of the gorse and Callunetum faunas exploited in the observed proportions, though some noxious taxa were avoided and below a certain limit, creatures of above average size were selected. Major foods were beetles, spiders, lepidopteran larvae and bugs. Nestling birds received a diet differing in taxonomic composition and size from that of the adults, and variations between habitats were found which accorded with observations on the habitat preferences of the Dartford warbler. An experimental investigation showed the importance of gorse as a source of food for young and the adults flew considerable distances ignoring extensive deep stands of heather nearer to the nest. The possible influence of competing insectivorous vertebrates on Dartford warblers is discussed. Various mammals and reptiles appeared to be the major vertebrate predators in Callunetum, but little competition was anticipated in gorse. Scarcity of gorse on the heaths and low densities of invertebrates in heather explained the low densities at which Dartford warblers occur.