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Post‐fledging survival of Sparrowhawks Accipiter nisus in relation to mass, brood size and brood composition at fledging
Author(s) -
NEWTON I.,
MOSS D.
Publication year - 1986
Publication title -
ibis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 80
eISSN - 1474-919X
pISSN - 0019-1019
DOI - 10.1111/j.1474-919x.1986.tb02094.x
Subject(s) - fledge , brood , accipiter , biology , zoology , ecology , population , demography , nest (protein structural motif) , predation , sociology , biochemistry
Using ring recoveries, the post‐fledging survival of Sparrowhawks was examined in relation to the growth rates and fledging masses of young and in relation to the size and sex composition of broods, which contained up to six young. On most aspects, no significant relationships were found: light young survived as well as heavy ones, both in the population as a whole and in individual broods; and young in large broods survived as well as young in small broods. This was attributed to relative food abundance in the post‐fledging dependency period and to the fact that most food‐related mortality among young occurs at an earlier stage in the breeding cycle. However, males in all‐male broods and females in all‐female broods survived slightly better after fledging than others of their sex in two‐sex broods. The reason is unknown.