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Modeling post-fledging survival of lark buntings in response to ecological and biological factors

Ecology

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Abstract

We evaluated the influences of several ecological, biological, and methodological factors on post-fledging survival of a shortgrass prairie bird, the Lark Bunting (Calamospiza melanocorys). We estimated daily post-fledging survival (n = 206, 82 broods) using radiotelemetry and color bands to track fledglings. Daily survival probabilities were best explained by drought intensity, time in season (quadratic trend), ages a??3 d post-fledging, and rank given drought intensity. Drought intensity had a strong negative effect on survival. Rank was an important predictor of fledgling survival only during the severe drought of 2002 when the smallest fledglings had lower survival. Recently fledged young (ages a??3 d post-fledging) undergoing the transition from nest to surrounding habitat experienced markedly lower survival, demonstrating the vulnerable nature of this time period. Survival was greater in mid and late season than early season, corresponding to our assumptions of food availability. Neither mark type nor sex of attending parent influenced survival. The model-averaged product of the 22-d survival calculated using mean rank and median value of time in season was 0.360 A? 0.08 in 2001 and 0.276 A? 0.08 in 2002. Survival estimates that account for age, condition of young, ecological conditions, and other factors are important for parameterization of realistic population models. Biologists using population growth models to elucidate mechanisms of population declines should attempt to estimate species-specific of post-fledging survival rather than use generalized estimates.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Modeling post-fledging survival of lark buntings in response to ecological and biological factors
Series title:
Ecology
Volume
87
Issue:
1
Year Published:
2006
Language:
English
Contributing office(s):
Fort Collins Science Center
Description:
p. 178-188
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
178
Last page:
188
Number of Pages:
11