Migration and wintering of the BlackcapSylvia atricapillaon a Mediterranean island

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Abstract
892 Blackcaps were ringed on a southern Italian island, Vivara (40°45'N, 13°58'E) near Naples, between Oćtober 1977 and December 1983, and morphological data were taken from the 569 birds caught between January 1980 and August 1983. The autumn migration peaked in October and November while the spring migration was mainly the return of local breeding birds. Mean monthly sex ratio was 0.51 (S.D. = 0.1); inequalities were found only in March (20 males vs. 9 females). Wing lengths of both sexes were significantly shorter during the breeding season than in winter due to the influx of longer‐winged migrants at the latter season. Males migrated earlier than females. An analysis of the recaptures indicated three groups of birds: a) autumn migrants with no recaptures (not even the next day after ringing; b) a small wintering group with recaptures of up to two months after ringing; c) breeders, recaptured several times, in the same and later years. Breeding birds left the island in September. No autumn‐ringed bird was recaptured in spring which might indicate either the use of different routes at the two seasons or that they overflew the island in spring.