Douglas Johnson (Former Employee)
Science and Products
Filter Total Items: 318
A review of the population estimation approach of the North American landbird conservation plan A review of the population estimation approach of the North American landbird conservation plan
As part of their development of a continental plan for monitoring landbirds (Rich et al. 2004), Partners in Flight (PIF) applied a new method to make preliminary estimates of population size for all 448 species of landbirds present in the continental United States and Canada (Table 1). Estimation of the global population size of North American landbirds was intended to (1) identify the...
Authors
Wayne E. Thogmartin, Frank P. Howe, Frances C. James, Douglas H. Johnson, Eric T. Reed, John R. Sauer, Frank R. Thompson
Patch size and landscape effects on density and nesting success of grassland birds Patch size and landscape effects on density and nesting success of grassland birds
Current 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...
Authors
Maiken Winter, Douglas H. Johnson, Jill A. Shaffer, Therese M. Donovan, W. Daniel Svedarsky
Proximate and landscape factors influence grassland bird distributions Proximate and landscape factors influence grassland bird distributions
Ecologists increasingly recognize that birds can respond to features well beyond their normal areas of activity, but little is known about the relative importance of landscapes and proximate factors or about the scales of landscapes that influence bird distributions. We examined the influences of tree cover at both proximate and landscape scales on grassland birds, a group of birds of...
Authors
M.A. Cunningham, Douglas H. Johnson
Conspecific attraction in a grassland bird, the Baird's Sparrow Conspecific attraction in a grassland bird, the Baird's Sparrow
Territorial songbirds generally use song to defend territories and attract mates, but conspecific song may also serve as a cue to attract other male songbirds to a breeding site. Although known to occur in some colonial and forest-associated species, only recently have investigators examined conspecific attraction in grassland species. We used a playback experiment to examine the...
Authors
M.A. Ahlering, Douglas H. Johnson, John Faaborg
Does body size affect a bird's sensitivity to patch size and landscape structure? Does body size affect a bird's sensitivity to patch size and landscape structure?
Larger birds are generally more strongly affected by habitat loss and fragmentation than are smaller ones because they require more resources and thus larger habitat patches. Consequently, conservation actions often favor the creation or protection of larger over smaller patches. However, in grassland systems the boundaries between a patch and the surrounding landscape, and thus the...
Authors
Maiken Winter, Douglas H. Johnson, Jill A. Shaffer
A fresh look at the taxonomy of midcontinental sandhill cranes A fresh look at the taxonomy of midcontinental sandhill cranes
The midcontinental population of sandhill crane (Grus canadensis) includes about 500,000 birds and provides valuable recreational crane-watching and hunting opportunities in Canada and the United States. It comprises three subspecies, one of which (G. c. rowani) was of uncertain taxonomic status and another of which (G. c. tabida) merited protection from excessive harvest due to its...
Authors
Douglas H. Johnson, Jane E. Austin, Jill A. Shaffer
Science and Products
Filter Total Items: 318
A review of the population estimation approach of the North American landbird conservation plan A review of the population estimation approach of the North American landbird conservation plan
As part of their development of a continental plan for monitoring landbirds (Rich et al. 2004), Partners in Flight (PIF) applied a new method to make preliminary estimates of population size for all 448 species of landbirds present in the continental United States and Canada (Table 1). Estimation of the global population size of North American landbirds was intended to (1) identify the...
Authors
Wayne E. Thogmartin, Frank P. Howe, Frances C. James, Douglas H. Johnson, Eric T. Reed, John R. Sauer, Frank R. Thompson
Patch size and landscape effects on density and nesting success of grassland birds Patch size and landscape effects on density and nesting success of grassland birds
Current 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...
Authors
Maiken Winter, Douglas H. Johnson, Jill A. Shaffer, Therese M. Donovan, W. Daniel Svedarsky
Proximate and landscape factors influence grassland bird distributions Proximate and landscape factors influence grassland bird distributions
Ecologists increasingly recognize that birds can respond to features well beyond their normal areas of activity, but little is known about the relative importance of landscapes and proximate factors or about the scales of landscapes that influence bird distributions. We examined the influences of tree cover at both proximate and landscape scales on grassland birds, a group of birds of...
Authors
M.A. Cunningham, Douglas H. Johnson
Conspecific attraction in a grassland bird, the Baird's Sparrow Conspecific attraction in a grassland bird, the Baird's Sparrow
Territorial songbirds generally use song to defend territories and attract mates, but conspecific song may also serve as a cue to attract other male songbirds to a breeding site. Although known to occur in some colonial and forest-associated species, only recently have investigators examined conspecific attraction in grassland species. We used a playback experiment to examine the...
Authors
M.A. Ahlering, Douglas H. Johnson, John Faaborg
Does body size affect a bird's sensitivity to patch size and landscape structure? Does body size affect a bird's sensitivity to patch size and landscape structure?
Larger birds are generally more strongly affected by habitat loss and fragmentation than are smaller ones because they require more resources and thus larger habitat patches. Consequently, conservation actions often favor the creation or protection of larger over smaller patches. However, in grassland systems the boundaries between a patch and the surrounding landscape, and thus the...
Authors
Maiken Winter, Douglas H. Johnson, Jill A. Shaffer
A fresh look at the taxonomy of midcontinental sandhill cranes A fresh look at the taxonomy of midcontinental sandhill cranes
The midcontinental population of sandhill crane (Grus canadensis) includes about 500,000 birds and provides valuable recreational crane-watching and hunting opportunities in Canada and the United States. It comprises three subspecies, one of which (G. c. rowani) was of uncertain taxonomic status and another of which (G. c. tabida) merited protection from excessive harvest due to its...
Authors
Douglas H. Johnson, Jane E. Austin, Jill A. Shaffer