Ringing & Migration Journal of the BTO Ringing Scheme

Ringing & Migration Volume 22 Part
Abstracts

[ For abstracts from Ringing Group Reports click here ]

Plumage temperatures of Dippers Cinclus cinclus on the roost and in the hand: implications for handling small passerines

JOHN DAVENPORT*, JOHN O’HALLORAN and PAT SMIDDY
Department of Zoology, Ecology and Plant Science, and Environmental Research Institute, University College Cork, Lee Maltings, Prospect Row, Cork, Ireland.

The outer breast plumage temperature of Dippers Cinclus cinclus roosting beneath river bridges was measured using an infra red thermometer over the environmental temperature range –0.8 to +10.9°C. Plumage temperature was close to, and directly related to, the temperature of the birds’ surroundings, but significantly higher (ΔT = 2.87°C), suggesting slight heat loss across the plumage to the environment. Plumage temperatures were also measured in Dippers held in the hand; they were much elevated over environmental temperatures (ΔT = 17-18°C at 0°C), indicating substantial heat loss during handling.

The Origins of moulting Goosanders on the Eden Estuary

P. LESLIE HATTON1 and M. MARQUISS2*
1Edenvale, Lydox Cottages, Dairsie, Fife KY15 4RN, UK 2Centre for Ecology & Hydrology, Hill of Brathens, Banchory AB31 4BW, UK

Moulting Goosanders were counted on the Eden estuary, Fife, UK from 1979 to 1994, and some of these birds were caught and wing-tagged from 1992 to 1994. This paper documents changes in numbers of moulting birds, and their provenance, as determined from subsequent sightings. Goosanders only started to moult on the Eden estuary in the 1980s and their numbers have increased since the late 1980s. This increase also occurred elsewhere on other, geographically similar, Scottish east-coast estuaries. The birds are adult females, and many, though not all, seem faithful to their moult site. Moulting flocks persist from June to October, with a turnover of birds occurring during this period. The moulting birds are drawn primarily from wintering and breeding areas to the south and west of the Eden estuary, in southwest Scotland, England and Wales.

Some aspects of Chaffinch Fringilla coelebs biology, based on an analysis of individuals ringed during 1991 to 2003 in Norfolk, England

STEPHEN J. BROWNE
The Game Conservancy Trust, Fordingbridge, Hampshire SP6 1EF, UK

From 1991 to 2003, 2,954 Chaffinches Fringilla coelebs were caught and ringed, year-round, at Hilborough, Norfolk, England. The age and sex composition of Chaffinches varied between winters, but no systematic pattern was apparent. The age and sex composition of Chaffinches caught during winter did not vary significantly from that of Chaffinches caught during the breeding season. Chaffinch wing lengths and body weights did not vary significantly between seasons. Male Chaffinches had wings that were on average 6 mm longer than females and adult wings were on average 2-3 mm longer than immatures and juveniles. Male Chaffinches were on average 2 g heavier than females. Approximately 40% of juvenile Chaffinches retained unmoulted greater coverts after their post-juvenile moult, retaining 1.47 ± 0.04 and 1.67 ± 0.09 for males and females respectively. Compared to immature females, twice as many immature males retained juvenile greater coverts. Over the period of study, Chaffinches showed relatively consistent annual productivity, with captures of between 1.5 and 2 times as many juveniles or immatures as adults during the months following the breeding season. The higher productivity in some years was not explained by variations in average monthly temperature during the breeding season. The mean duration between initial and final capture on the study site was between 1.6 and 2.3 years, and the longest period between initial capture and last recapture was over ten years. Only 0.14% of Chaffinches were recorded moving distances greater than 5 km from the site of capture, confirming the sedentary nature of the species. This study shows that few, if any, continental immigrants supplement the local Chaffinch population at the study site in Norfolk.

Bird ringing in Britain and Ireland in 2003

Jacquie A. Clark*, Robert A. Robinson, Dawn E. Balmer, Sue Y. Adams, Mark P. Collier, Mark J. Grantham, Jeremy R. Blackburn and Bridget M. Griffin
BTO, The Nunnery, Thetford, Norfolk IP24 2PU, UK

This is the 67th annual report of the British Trust for Ornithology’s Ringing Scheme, covering work carried out, and data received, in 2003. During the year, reports of ringed birds were used to assess the post-release survival of rehabilitated individuals. Varying proportions of different species were able to re-enter the population, with Mute Swan Cygnus olor being the most successful. The origins and age structure of Guillemots Uria aalge ringed in Britain & Ireland and found dead after five major oil spills in European waters were found to vary depending on the location of the oil spill. More immature birds and birds from eastern colonies tended to be found after spills that were further south, whereas spills in the north had a greater effect on adults and birds from western colonies. Work on mass gain strategies in Blackbirds Turdus merula showed that they put on mass in winter, when the threat of starvation is greatest, as well as changing mass through the day, again probably in response to the likelihood of starvation. A study of the survival of passerines in the few weeks after fledging found that the survival rate during this critical period is only about one sixth of the rate in the rest of the first year of life. A study of the demography of Spotted Flycatcher Muscicapa striata showed that changes in post fleding survival were the most likely mechanism for the observed population decline. Data gathered as part of the Constant Effort Sites (CES) Scheme showed that adult abundance among resident species was generally high, following a good breeding season in 2002. When compared to 2002, fledgling productivity in 2003 was lower, probably as a result of cold, wet weather during the breeding season. A total of 111 Retrapping Adults for Survival (RAS) studies submitted data covering 43 species. Target species for future work were identified. Continuing work on the winter movements of farmland passerines showed variations in the distances moved by different species. Over 11,000 Swallows Hirundo rustica were ringed as part of the Swallow Roost Project. The total number of birds ringed (848,532) increased for the second year and was 5% above the mean of the previous five years (1998-2002). The recovery total (11,554) was also 5% up on the five-year mean (1998-2002). Recoveries of 180 BTO-ringed birds and 76 ringed abroad are presented in the report; those included confirm known or suspected movement patterns or are unexpected movements.

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