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Abstract Many animals disperse from their natal sites as juveniles to settle in new locations where they may eventually breed. Estimating distances of such postnatal dispersal within and across populations, as well as identifying factors affecting recruitment success, is important for understanding the evolutionary consequences of dispersal. We investigated patterns of postnatal dispersal and identified predictors of successful recruitment in highly resident Poecile gambeli (Mountain Chickadee) using data on 326 recruits of 5,226 total fledglings detected at winter feeders (recruitment into winter flocks) and nest boxes (recruitment into the breeding population) over 12 years at 2 elevational sites in the northern Sierra Nevada, USA. Like most Parids, chickadees dispersed close to their natal sites (median distance: 644 m). Dispersal distance was not associated with fledgling mass, but females dispersed significantly longer distances than males. When only considering dispersal distances based on recaptures at nest boxes, birds that fledged earlier dispersed significantly shorter distances. Successful recruitment both into winter flocks and into the breeding population was associated with higher fledgling mass and earlier fledging. Over the study period, only 13 birds were detected dispersing from one elevational site to the other, and 12 of these birds hatched at low elevation and dispersed to the high-elevation site. Our results suggest that earlier fledging timing and higher fledgling mass are both critical for successful recruitment in P. gambeli and confirm that fledgling mass is a key measure of individual quality in which even small differences in mass (~2%–3%) may have important implications for recruitment and, therefore, fitness.
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Reproductive benefits associated with dispersal in headwater populations of Trinidadian guppies ( Poecilia reticulata )
Abstract Theory suggests that the evolution of dispersal is balanced by its fitness costs and benefits, yet empirical evidence is sparse due to the difficulties of measuring dispersal and fitness in natural populations. Here, we use spatially explicit data from a multi‐generational capture–mark–recapture study of two populations of Trinidadian guppies (Poecilia reticulata) along with pedigrees to test whether there are fitness benefits correlated with dispersal. Combining these ecological and molecular data sets allows us to directly measure the relationship between movement and reproduction. Individual dispersal was measured as the total distance moved by a fish during its lifetime. We analysed the effects of dispersal propensity and distance on a variety of reproductive metrics. We found that number of mates and number of offspring were positively correlated to dispersal, especially for males. Our results also reveal individual and environmental variation in dispersal, with sex, size, season, and stream acting as determining factors.
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- Award ID(s):
- 2016569
- PAR ID:
- 10445878
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Ecology Letters
- Volume:
- 25
- Issue:
- 2
- ISSN:
- 1461-023X
- Page Range / eLocation ID:
- p. 344-354
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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