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Full-Text Articles in Life Sciences
Breeding Time In A Migratory Songbird Is Predicted By Drought Severity And Group Size, Charles R. Brown, Mary Bomberger Brown
Breeding Time In A Migratory Songbird Is Predicted By Drought Severity And Group Size, Charles R. Brown, Mary Bomberger Brown
School of Natural Resources: Faculty Publications
Global climate change is altering the breeding phenology of many organisms, and one reported consequence of warmer average temperatures is earlier breeding times in migratory songbirds of north temperate latitudes. Less studied are the potential interactions between earlier breeding and social behavior in colonial species. We investigated how breeding time, as measured by colony initiation dates across the entire summer, in Cliff Swallows (Petrochelidon pyrrhonota) of southwestern Nebraska, USA, changed over a 30-year period and could be predicted by climatic variables, year, and colony size. Mean colony initiation date became earlier over the study, with variation best predicted …
The Relative Importance Of Patch Area And Perimeter–Area Ratio To Grassland Breeding Birds, Christopher J. Helzer, Dennis E. Jelinski
The Relative Importance Of Patch Area And Perimeter–Area Ratio To Grassland Breeding Birds, Christopher J. Helzer, Dennis E. Jelinski
School of Natural Resources: Faculty Publications
Habitat fragmentation has been implicated as a major cause of population decline in grassland birds. We tested the hypothesis that a combination of area and shape determines the use of grassland patches by breeding birds. We compared both species richness and individual species presence in 45 wet meadow grasslands in the floodplain of the central Platte River, Nebraska. Bird data were collected through the use of belt transects and supplemented by walking and listening outside transects. Our data supported our primary hypothesis that perimeter–area ratio, which reflects both the area and shape of a patch, is the strongest predictor of …