02681nas a2200145 4500008004100000245009500041210006900136260004200205300001100247490002100258520217200279100001602451700002102467856004702488 2012 eng d00aEcology of mating patterns and sexual selection in dickcissels breeding in managed prairie0 aEcology of mating patterns and sexual selection in dickcissels b aLexington, KYbUniversity of Kentucky a1 -1660 vPhD Dissertation3 a
Males of many species have elaborate phenotypes that are absent in females and that are thought to be the result of sexual selection. Sexual selection requires: (i) variance in male mating success, (ii) variation in male phenotype, and (iii) covariation between male mating success and male phenotype. Environmental conditions influence these factors, and management practices that alter environmental conditions have the potential to shape mating patterns and sexual selection. I investigated the hypothesis that the frequency of fire, used to manage tallgrass prairie, affects the mating patterns and process of sexual selection in the organisms breeding in managed prairies. I studied dickcissels (Spiza americana), a small songbird resident in tallgrass prairie. I first examined mating patterns and sexual selection in dickcissels independent of burning regime. I found variation among males in the number of mates attracted, in the number of offspring sired with each mate, and the offspring sired with the mates of other males. I found a positive association between social mates and siring success, but no evidence for an effect of breeding density or synchronous nesting on mating success. Male dimorphic traits, size, song, and plumage, showed between-individual variation but selection gradients were weak and often fluctuated between the years of study. I next examined patterns of mating success in plots burned on a variable schedule. I found little evidence that burning influenced either the mean or the variance in social mating success, paternity, or male phenotype. Burning regime also had no influence on sexual selection gradients with the single exception of selection on tarsus length. Temporal variation was more important for patterns of mating success and sexual selection gradients on male traits than was burning regime. The demography of dickcissels in the breeding season suggests, however, that habitat management on a larger scale may be more influential. My findings extend our understanding of sexual selection in birds and the effects of management on the factors required for sexual selection and the magnitude of selection.
1 aSousa, B.F.1 aWestneat, D., F. uhttp://uknowledge.uky.edu/biology_etds/17/01489nas a2200133 4500008004100000245007700041210006900118300001300187490000700200520103500207100001601242700002001258856007701278 2011 eng d00aDesign and effectiveness of a novel trap for capturing nesting songbirds0 aDesign and effectiveness of a novel trap for capturing nesting s a425 -4290 v823 aCapturing songbirds at their nests can be challenging and time consuming. Although traps designed for capturing songbirds at their nests have been described in the literature, few are effective for capturing species with open-cup nests. We describe a cylindrical trap designed to capture songbirds at nests up to 2 m above ground in grasses, forbs, shrubs, and small saplings. The nest trap is constructed using a rigid hoop, two pieces of mist net, three stakes, and twist ties. We used this trap to capture female Dickcissels (Spiza americana) and female Indigo Buntings (Passerina cyanea) at their nests, with success rates of 85% (N= 196) and 60–73% (N= 16), respectively. Trapping success was comparable to that using other passerine nest trap designs. Nest abandonment after trapping attempts was rare and similar to that reported in previous studies. Our nest trap is lightweight, easy to make, versatile enough to use in a variety of grassland and shrub habitats, and easily carried and deployed in the field.
1 aSousa, B.F.1 aStewart, S.L.M. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/j.1557-9263.2011.00346.x