Factors affecting nesting success of wood thrushes in Great Smoky Mountains National Park

Citation
Gl. Farnsworth et Tr. Simons, Factors affecting nesting success of wood thrushes in Great Smoky Mountains National Park, AUK, 116(4), 1999, pp. 1075-1082
Citations number
35
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences
Journal title
AUK
ISSN journal
0004-8038 → ACNP
Volume
116
Issue
4
Year of publication
1999
Pages
1075 - 1082
Database
ISI
SICI code
0004-8038(199910)116:4<1075:FANSOW>2.0.ZU;2-F
Abstract
Recent evidence suggests that the nesting success of forest-interior Neotro pical migrants is lower in fragmented habitat. We examined the nesting succ ess of Wood Thrushes (Hylocichla mustelina) in a large contiguous forest fr om 1993 to 1997. From a sample of 416 nests we tested for predictors of dai ly nest survival rates, including activity at the nest and vegetation param eters at the nest site. We tested whether disturbance during nest checks la s measured by the behavior of the adults) was related to subsequent nest pr edation. Females were more likely to vocalize when brooding chicks than whe n incubating eggs. However, we found no evidence that observer disturbance or Wood Thrush activity influenced daily nest survival rates. Wood Thrushes nested predominately in small hemlocks, generally surrounded by many other small hemlocks. However, survival rates of nests in hemlocks were not sign ificantly different from those in other substrates. Overall, neither activi ty at the nest nor habitat in the vicinity of the nest was a good predictor of nesting success, and only one vegetation characteristic, a measure of c oncealment, was significantly correlated with successful nesting. Brood par asitism by Brown-headed Cowbirds (Molothrus ater) was extremely low (<2% of nests parasitized). However, nesting success was moderate (daily survival rate = 0.958) when compared with other published studies from more-fragment ed landscapes. Our results suggest that daily nest survival rates do not in crease monotonically from small to very large forest patches.