Spring migration of the garden warbler (Sylvia borin) across the Mediterranean Sea

Citation
A. Grattarola et al., Spring migration of the garden warbler (Sylvia borin) across the Mediterranean Sea, J ORNITHOL, 140(4), 1999, pp. 419-430
Citations number
37
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences
Journal title
JOURNAL FUR ORNITHOLOGIE
ISSN journal
0021-8375 → ACNP
Volume
140
Issue
4
Year of publication
1999
Pages
419 - 430
Database
ISI
SICI code
0021-8375(199910)140:4<419:SMOTGW>2.0.ZU;2-R
Abstract
Information concerning the strategy adopted by passerine migrants in crossi ng ecological barriers is still scant, especially as far as spring migratio n is concerned. With the aim of investigating the pattern of desert and sea crossing in spring, capture frequency, biometry and physical conditions of Garden Warblers ringed at 18 stations spread over the Western and Central Mediterranean were analysed as a function of the geographical position of t he ringing sites. The patterns of increasing capture frequency and wing len gth with longitude, matching those recorded within the species' wide breedi ng range, suggest wide-front movements across the Sahara and Mediterranean. The progressively delayed trapping hour with latitude indicates that Garde n Warblers migrate actively during the day. Despite the potentially favoura ble spring ecological conditions, the North African coast seems not to be u sed substantially to restore the reserves depleted during the desert crossi ng. According to recent estimates of flight range, fat levels recorded at o ur Mediterranean stations are compatible with the absence of refuelling in North Africa, assuming a fat load at departure of about 27 g or lower fat l oad and some tail wind assistance.