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Full-Text Articles in Social and Behavioral Sciences
Patch Size And Landscape Effects On Density And Nesting Success Of Grassland Birds, Maiken Winter, Douglas H. Johnson, Jill A. Shaffer, Therese M. Donovan, W. Daniel Svedarsky
Patch Size And Landscape Effects On Density And Nesting Success Of Grassland Birds, Maiken Winter, Douglas H. Johnson, Jill A. Shaffer, Therese M. Donovan, W. Daniel Svedarsky
USGS Northern Prairie Wildlife Research Center
Cumnt management recommendations for grassland birds in North America emphasize providing large patches of grassland habitat within landscapes that have few forest or shrubland areas. These Bird Conservation Areas are being proposed under the assumption that large patches of habitat in treeless landscapes will maintain viable populations of grassland birds. This assumption requires that patch size and landscape features affect density and nesting success of grassland birds, and that these effects are consistent among years and regions and across focal species. However, these assumptions have not yet been validated for grassland binls, and the relative importance of local vegetation structure, …
Variability In Vegetation Effects On Density And Nesting Success Of Grassland Birds, Maiken Winter, Douglas H. Johnson, Jill A. Shaffer
Variability In Vegetation Effects On Density And Nesting Success Of Grassland Birds, Maiken Winter, Douglas H. Johnson, Jill A. Shaffer
USGS Northern Prairie Wildlife Research Center
The structure of vegetation in grassland systems, unlike that in forest systems, varies dramatically among years on the same sites, and among regions with similar vegetation. The role of this variation in vegetation structure on bird density and nesting success of grassland birds is poorly understood, primarily because few studies have included sufficiently large temporal and spatial scales to capture the variation in vegetation structure, bird density, or nesting success. To date, no large-scale study on grassland birds has been conducted to investigate whether grassland bird density and nesting success respond similarly to changes in vegetation structure. However, reliable management …
Guidelines For Finding Nests Of Passerine Birds In Tallgrass Prairie, Maiken Winter, Shawn E. Hawks, Jill A. Shaffer, Douglas H. Johnson
Guidelines For Finding Nests Of Passerine Birds In Tallgrass Prairie, Maiken Winter, Shawn E. Hawks, Jill A. Shaffer, Douglas H. Johnson
USGS Northern Prairie Wildlife Research Center
The productivity of birds is one of the most critical components of their natural history affected by habitat quality. Birds might occur at high densities in a given habitat patch but have low nesting success. Such "population sinks" would not be detected if observers relied solely on estimates of bird density. Therefore, it is essential to monitor nests and determine their outcomes. Although interest in grassland-nesting passerines has increased greatly during the last decade, we still know little about factors affecting their nesting success. To stimulate more research in this area, we summarize several methods for nest-searching and provide suggestions …
Effects Of Leafy Spurge Infestation On Grassland Birds, Daniel M. Scheiman, Eric K. Bollinger, Douglas H. Johnson
Effects Of Leafy Spurge Infestation On Grassland Birds, Daniel M. Scheiman, Eric K. Bollinger, Douglas H. Johnson
USGS Northern Prairie Wildlife Research Center
Grassland bird populations are declining. Invasive plant species may be contributing to these declines by altering habitat quality. However, the effects of invasive plants on grassland birds are largely unknown. Leafy spurge (Euphorbia esula) is an exotic, invasive weed in the northern Great Plains. We examined the effects of leafy spurge infestation on densities of breeding birds, nest-site selection, and nest success in grasslands on the Sheyenne National Grassland (SNG), North Dakota, USA, 1999-2000. We categorized spurge-infested grasslands into 3 groups (low, medium, high), based on the area covered by spurge patches. We surveyed 75 100-m-radius circular points …