Ringing & Migration Journal of the BTO Ringing Scheme

Ringing & Migration Volume 20 Part 3
Abstracts

[ For abstracts from Ringing Group Reports click here ]

Moult and ageing of Storm Petrels Hydrobates pelagicus

M. BOLTON¹ and R. THOMAS²*
¹ A Rocha Field Study Centre, Cruzinha, Apt 41, 8500 Mexilhoeira Grande, Algarve, Portugal
² School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS81UG, UK

Current published ageing criteria for Storm Petrels, Hydrobates pelagicus appear to be unreliable, so fledged birds are not aged to a high degree of accuracy, restricting the scope of age-specific studies. Analyses of moult and feather wear were carried out on 28 specimens of Storm Petrels which were washed ashore on the southern coast of Portugal during January 1996, and on a further 780 live individuals which were trapped during May-July 1998, also on the southern coast of Portugal. Differences in the pattern of wear and bleaching of the primary feathers between those grown simultaneously in the nest and those grown sequentially over a long period by older birds, allows fledged individuals to be aged as in their first year, or older. Using primary wear to age individuals, the shape of the outermost long primary feather can then also be shown to be a reliable ageing criterion. Some birds in active primary moult can be aged even more specifically by a combination of primary wear and the shape of the outermost primary.

June broods are of greatest benefit to Sand Martins Riparia riparia

E. COWLEY
The Upper Cottage, Argrennan Mains, Tongland, Kirkcudbright DG6 4NE, UK

This work examines the retrap rate in subsequent years of Sand Martins Riparia riparia ringed as juveniles in colonies in Nottinghamshire from 1969 to 1991. It shows that the weight of juveniles fledging with primaries still partially in pin fell until the primaries were fully developed. This is a hazardous time and at least one-third of them died during this period whilst they were still dependent on their parents until they learned to forage for themselves. 19/322 (5.9%) with primaries 6 or 7-9 partially in pin were retrapped in future years compared with 78/865 (9.0%) with primaries 8-9 or primary 9 alone partially in pin. The subsequent-year retrap rate decreased dramatically for juveniles examined as the day length shortened. 38/368 (10.3%) of juveniles with primaries partially in pin when examined in June were retrapped in subsequent years but this proportion fell to 47/527 (8.9%) in July, 10/186 (5.4%) in August and 1/91 (1.1%) in September. This is probably because the juveniles fledging earlier in the season survived the immediate post-fledging period better. Data from an intensive part of this study suggest that they stayed around their natal colony for a median of six days in June increasing to 12 days in September.

A model describing the exchange of individuals between Turnstone Arenaria interpres roosts on the North Wales coast

JAMES W. PEARCE-HIGGINS*
School of Biological Sciences, 3.239 Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK

SHORT NOTE

Reaction of Redshank Tringa totanus to colour-rings

NIALL H. K. BURTON*
British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU, UK

Body weight variation and fat deposition in Common Sandpipers Actitis hypoleucos L. during their autumn migration in the Ría de Vigo, Galicia, north-west Spain

J. ARCAS.
Laboratorio de Anatomía Animal. Departamento de Ecología y Biología Animal. Facultad de Ciencias. Universidad de Vigo. Apartado 874. 36200 Vigo (Pontevedra), Spain

SHORT NOTE

The use of primary abrasion for ageing Reed Buntings Emberiza schoeniclus

JAVIER DE LA PUENTE and JAVIER SEOANEGrupo Ornitológico SEO-Monticola, Edificio de Biología, Unidad de Zoología, Universidad Autónoma de Madrid, E-28049, Madrid, Spain

Identification of Marsh Warblers Acrocephalus palustris and Reed Warblers A. scirpaceus on autumn migration through the eastern Mediterranean

JEREMY D. WILSON¹*, TRIANTAPHYLLOS AKRIOTIS², DAWN E. BALMER³ and ANTONIOS KYRKOS^4
1 RSPB, The Lodge, Sandy, Bedfordshire SG19 2DL, UK
² Department of Environmental Studies, University of the Aegean, Karantoni 17, GR-81100 Mytilini, Greece
³ British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU, UK
⁴ Edward Grey Institute of Field Ornithology, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK

The spring stopover of the Reed Warbler Acrocephalus scirpaceus in northeast Spain

DAVID ROBSON*, CARLES BARRIOCANAL, OSCAR GARCIA and OSCAR VILLENA
Provenza, 139 5-1 08036 Barcelona, Spain

The patterns of spring stopover of the Reed Warbler Acrocephalus scirpaceus were investigated at a coastal site in northeast Spain between 1993 and 1997. Birds arrived in good physiological condition, with a mean fat load of 10%. There was a seasonal decline in wing length and fat load, suggesting that larger and fatter birds migrate earlier. Only 4.3% of the birds stopped over for more than one day. These birds carried lower fat loads and had a later capture time than transients. In addition they tended to show no increase in mass during their stopover although this can be an effect of birds in different stages of their migratory journey. Birds at our site had a mean stopover length of one day, enough to gain sufficient fat stores to reach the next feeding site. This strategy may be expected in spring, when birds are under selection pressure to minimize migration time.

Bird Ringing in Britain and Ireland in 1999

JACQUIE A. CLARK, CHRIS V. WERNHAM, DAWN E. BALMER, SUE Y. ADAMS, BRIDGET M. GRIFFIN, JEREMY R. BLACKBURN, DAVE ANNING and LINDA J. MILNE

This is the 63rd annual report of the British Trust for Ornithology’s Ringing Scheme presenting work carried out and data received in 1999. A study of long-term trends in songbird productivity using constant effort ringing showed that changes have been markedly synchronised through time for some groups of ecologically similar species (eg resident insectivores, Blackbird and Song Thrush, Blue Tit and Great Tit). Significant decreases were found in the productivity (juvenile: adult ratio) of 15 of the 26 species, and no significant increases. For 14 species, higher temperatures over the summer months resulted in lower productivity, and greater total summer rainfall was associated with higher productivity for 11 species. Significant differences between regions of Britain & Ireland were detected for 11 species, highlighting the importance of maintaining sufficient numbers of monitoring sites to carry out analyses at the regional level. Comparison with nest record data showed that, for three species, the falling productivity may be a result of a decline in the number of nesting attempts or the immediate post-fledging survival of young. Some changes in productivity were linked to changes in abundance; for others a density-dependent negative change in productivity may have taken place and, for at least two species, changes in survival rates may be driving the observed population decline. Survival rates of adults of two declining species, Blackbird and Song Thrush, were measured using Constant Effort Sites (CES) data from 1983 to 1998. The annual survival of Blackbirds declined significantly and a strong relationship between annual survival rates and winter temperatures was found. A study of the declines in populations of Oystercatchers and Knot on the Wash found that winter survival rates of adult Oystercatchers have remained approximately constant (98%) from 1990 to 1998, except during three years of unusually low survival when both cockle and mussel stocks were low. Adult winter survival rates of Knot were more variable (70-97%). Indices of mussel and cockle stock size were significant in determining the over-winter survival rate of Oystercatchers but did not influence those of Knot. An analysis of ring-recovery and nest record data for Spotted Flycatcher showed that increasing mortality in the first year of life is likely to be responsible for the recent acceleration in the decline of this species. Data collected by the CES Scheme suggested that weather conditions during the 1999 breeding season resulted in mixed fortunes for Britain and Ireland’s common songbirds. Adult numbers were significantly greater in 1999 than in 1998 for two species (Wren and Sedge Warbler) and significantly lower for three species (Chiffchaff, Willow Warbler and Blue Tit). Productivity (the percentage of juveniles in catches) was significantly lower for two species (Blackcap and Redpoll). 1999 was the second year of the Retrapping Adults for Survival (RAS) Project and 85 datasets covering 34 species were received. The number of birds ringed in 1999 (700,387) represents a 16% decrease from the five-year mean 1994-1998. The recovery total (10,586) was 13% lower than the mean of the previous five years (1994-1998). Recoveries of 183 BTO-ringed birds and 110 birds ringed abroad are presented in the report, including a number of significant movements of an unusual nature. Particularly noteworthy were two Storm Petrels found in Switzerland following a hurricane and a Pied Flycatcher ringed in the nest in Asian Russia (85° E) in late June and recaptured less than three months later in Yorkshire.

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