Fattening strategies of British & Irish Barn Swallows Hirundo rustica prior to autumn migration

Publication Type:Journal Article
Year of Publication:2011
Authors:Coiffait, L, Robinson, RA, Clark, JA, Griffin, BM
Journal:Ringing & Migration
Volume:26
Issue:1
Date Published:2011
ISBN Number:0307-8698
Keywords:Europe, Hirundinidae, Hirundo, Hirundo rustica, Ireland, Italy, Southern Europe, Spain, United Kingdom
Abstract:For migratory birds, regulation of energy reserves is crucial for survival during the migratory journey, and may also affect subsequent stages of the life cycle. Although Barn Swallows Hirundo rustica are able to feed en route, recent studies in Italy and Spain have demonstrated that they accumulate fat stores prior to departing for the wintering grounds. We investigated factors affecting pre-migratory body-mass gain in Swallows roosting at 41 sites in Britain & Ireland using data from 543 catches between July and September in 2002?06. Mean body mass of both adult and juvenile Swallows increased prior to migration, but adults gained more mass than juveniles. There was strong evidence that the increase was a result of birds building up fat reserves in preparation for migration. Swallows caught at more-southerly roosts developed larger fuel reserves than those caught in the north. The pattern of body-mass increase mirrored that of birds caught in southern Europe, although British & Irish Swallows gained less mass and fattening began earlier. These results suggest that British & Irish Swallows may stage in southern Britain, gaining sufficient fuel reserves to allow them to travel to the Continent, where further fattening is likely to occur.For migratory birds, regulation of energy reserves is crucial for survival during the migratory journey, and may also affect subsequent stages of the life cycle. Although Barn Swallows Hirundo rustica are able to feed en route, recent studies in Italy and Spain have demonstrated that they accumulate fat stores prior to departing for the wintering grounds. We investigated factors affecting pre-migratory body-mass gain in Swallows roosting at 41 sites in Britain & Ireland using data from 543 catches between July and September in 2002?06. Mean body mass of both adult and juvenile Swallows increased prior to migration, but adults gained more mass than juveniles. There was strong evidence that the increase was a result of birds building up fat reserves in preparation for migration. Swallows caught at more-southerly roosts developed larger fuel reserves than those caught in the north. The pattern of body-mass increase mirrored that of birds caught in southern Europe, although British & Irish Swallows gained less mass and fattening began earlier. These results suggest that British & Irish Swallows may stage in southern Britain, gaining sufficient fuel reserves to allow them to travel to the Continent, where further fattening is likely to occur.
URL:http://www.tandfonline.com/doi/abs/10.1080/03078698.2011.586583
Short Title:Ringing & Migration
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith