| density-dependent habitat selection by brown-headed cowbirds ( molothrus ater) in tallgrass prairie. | local distributions of avian brood parasites among their host habitats may depend upon conspecific parasite density. we used isodar analysis to test for density-dependent habitat selection in brown-headed cowbirds ( molothrus ater) among tallgrass prairie adjacent to wooded edges, and prairie interior habitat (>100 m from wooded edges) with and without experimental perches. eight study sites containing these three habitat treatments were established along a geographical gradient in cowbird abund ... | 2005 | 15375686 |
| habitat edge, land management, and rates of brood parasitism in tallgrass prairie. | bird populations in north america's grasslands have declined sharply in recent decades. these declines are traceable, in large part, to habitat loss, but management of tallgrass prairie also has an impact. an indirect source of decline potentially associated with management is brood parasitism by the brown-headed cowbird (molothrus ater), which has had substantial negative impacts on many passerine hosts. using a novel application of regression trees, we analyzed an extensive five-year set of ne ... | 2006 | 16711055 |
| grassland bird responses to land management in the largest remaining tallgrass prairie. | extensive habitat loss and changing agricultural practices have caused widespread declines in grassland birds throughout north america. the flint hills of kansas and oklahoma--the largest remaining tallgrass prairie--is important for grassland bird conservation despite supporting a major cattle industry. in 2004 and 2005, we assessed the community, population, and demographic responses of grassland birds to the predominant management practices (grazing, burning, and haying) of the region, includ ... | 2009 | 19040653 |
| assessing multiregion avian benefits from strategically targeted agricultural buffers. | mounting evidence of wildlife population gains from targeted conservation practices has prompted the need to develop and evaluate practices that are integrated into production agriculture systems and targeted toward specific habitat objectives. however, effectiveness of targeted conservation actions across broader landscapes is poorly understood. we evaluated multiregion, multispecies avian densities on row-crop fields with native grass field margins (i.e., buffers) as part of the first u.s. agr ... | 2014 | 24779636 |
| markov chain estimation of avian seasonal fecundity. | avian seasonal fecundity is of interest from evolutionary, ecological, and conservation perspectives. however, direct estimation of seasonal fecundity is difficult, especially with multi-brooded birds, and models representing the renesting and quitting processes are usually required. to explore the consequences of modeling decisions on inference about avian seasonal fecundity, we generalize previous markov chain (mc) models of avian nest success to formulate two different mc models of avian seas ... | 2009 | 19425426 |
| modeling age and nest-specific survival using a hierarchical bayesian approach. | recent studies have shown that grassland birds are declining more rapidly than any other group of terrestrial birds. current methods of estimating avian age-specific nest survival rates require knowing the ages of nests, assuming homogeneous nests in terms of nest survival rates, or treating the hazard function as a piecewise step function. in this article, we propose a bayesian hierarchical model with nest-specific covariates to estimate age-specific daily survival probabilities without the abo ... | 2009 | 19302407 |
| do habitat preferences improve fitness? context-specific adaptive habitat selection by a grassland songbird. | animals are predicted to prefer high-quality over low-quality habitats, but adaptive habitat selection is less straightforward than often assumed. preferences may improve only specific fitness metrics at particular spatial scales, with variation across time or between sexes. preferences sometimes even reduce fitness. we investigated the context specificity of adaptive habitat selection, studying dickcissels (spiza americana)-a polygynous songbird-as a model. from 2014 to 2015, we measured male a ... | 2020 | 32201907 |
| species-specific and temporal scale-dependent responses of birds to drought. | global climate change is increasing the frequency and intensity of weather extremes, including severe droughts in many regions. drought can impact organisms by inhibiting reproduction, reducing survival and abundance, and forcing range shifts. for birds, considering temporal scale by averaging drought-related variables over different time lengths (i.e., temporal grains) captures different hydrologic attributes which may uniquely influence food supplies, vegetation greenness/structure, and other ... | 2019 | 31025464 |
| haemosporidian parasite infections in the dickcissel ( spiza americana): prevalence and costs. | haemosporidian parasites are widespread in birds and are commonly used to evaluate ecological, evolutionary, and behavioral consequences of pathogen infection. while haemosporidian parasites may be important agents of selection, information on the incidence and outcomes of infection in many wild birds remains incomplete and warrants further inquiry. we examined the prevalence and costs of haemosporidian parasites in a wild population of dickcissels ( spiza americana; n = 170) breeding in central ... | 2019 | 30908117 |