Winter Roost Research Articles

Recent Advances in Bird-Ringing

BIRD-RINGING in Britain, now organized from the bird room of the British Museum (Natural History), shows an increase not in the actual number of birds marked, but in the number of adult birds ‘trapped’ and thus marked and released, and a decrease in the number of nestlings marked; the mortality amongst nestlings is naturally high and thus the chances of recovery of ringed nestlings fewer. The statistics for 1937 show that 45,181 birds were ringed in Britain (British Birds, April 1938), as against 48,663 the previous year, bringing the grand total of birds marked in the country since the scheme was started in 1907 to 575,914. There was a record total of ‘trapped’ birds last year of 21,900 compared with 19,235 birds last year, and it includes a number of rarities not marked before, such as the waxwing and little bunting. Skokholm Bird Observatory, South Wales, for example, marked 4,402 birds in 1937, including the valuable total of 1,448 Manx shearwaters, 904 gannets and 603 razorbills. Mr. G. Charteris's list of 3,044 birds marked included 1,396 chaffinches, mostly at a winter roost ; Mr. P. Morshead's total of 2,546 birds included 1,272 ‘trapped’ starlings ; Mr. A. Maynall's 2,024 birds including 348 nestling nightingales. The Zoological Society of London (through Mr. E. A. Billet) ringed a total of 1,144 birds at Whipsnade last year, these including 333 ‘trapped’ jackdaws. Some of the leading boys' schools again take a prominent place in the ringing returns. Owing to the increased cost of the rings and the organization, there is an appeal for funds in addition to the general charges for the rings used.

Winter Roosting Colonies of Crows

Crows constitute one of the most sagacious, gregarious, and omnivorous genera of birds. Throughout their wide distribution they form colonies which may be either small and of the family nature, where the crows do not migrate but live together throughout the year, or of large aggregations, composed mainly of migrants collecting together for the winter. In this country their winter colonies are found at or about 40? N. latitude along the Atlantic coast and in the valley of the Mississippi. They are so populous and so well organized, and their roosts so permanent, that they afford one of the best fields for the psychologist to study the manifestations of the social instinct. Although various phases of their gregarious habit have been recorded by a number of observers, there has hitherto been no systematic attempt to present the topic as a whole, including study of individual colonies, the number of colonies, with a general conspectus of the American literature and legislation upon the subject, such as is attempted in this preliminary report, to be followed by more detailed study of special phases later. The importance of the topic for all interested in what, since Palmen and Beard, might almost be called the philosophy of bird migration, or in the study of those