Douglas Johnson (Former Employee)
Science and Products
Filter Total Items: 318
Influences of environmental and anthropogenic features on greater sage-grouse populations, 1997-2007 Influences of environmental and anthropogenic features on greater sage-grouse populations, 1997-2007
The Greater Sage-Grouse (Centrocercus urophasianus), endemic to western North Amer-ica, is of great conservation interest. Its popula-tions are tracked by spring counts of males at lek sites. We explored the relations between trends of Greater Sage-Grouse lek counts from 1997 to 2007 and a variety of natural and anthropogenic fea-tures. We found that trends were correlated with several...
Authors
Douglas H. Johnson, Matthew J. Holloran, John W. Connelly, Steven E. Hanser, Courtney L. Amundson, Steven T. Knick
Conserving migratory land birds in the New World: Do we know enough? Conserving migratory land birds in the New World: Do we know enough?
Migratory bird needs must be met during four phases of the year: breeding season, fall migration, wintering, and spring migration; thus, management may be needed during all four phases. The bulk of research and management has focused on the breeding season, although several issues remain unsettled, including the spatial extent of habitat influences on fitness and the importance of...
Authors
John Faaborg, Richard T. Holmes, A.D. Anders, K.L. Bildstein, K.M. Dugger, S.A. Gauthreaux, P. Heglund, K.A. Hobson, A.E. Jahn, Douglas H. Johnson, S.C. Latta, D.J. Levey, P.P. Marra, C.L. Merkord, E. Nol, S.I. Rothstein, T.W. Sherry, Sillett T. Scott, F. R. Thompson, N. Warnock
Feeding ecology of arctic-nesting sandpipers during spring migration through the prairie pothole region Feeding ecology of arctic-nesting sandpipers during spring migration through the prairie pothole region
We evaluated food habits of 4 species of spring-migrant calidrid sandpipers in the Prairie Pothole Region (PPR) of North Dakota. Sandpipers foraged in several wetland classes and fed primarily on aquatic dipterans, mostly larvae, and the midge family Chironomidae was the primary food eaten. Larger sandpiper species foraged in deeper water and took larger larvae than did smaller...
Authors
J.L. Eldridge, Gary L. Krapu, Douglas H. Johnson
Area sensitivity in North American grassland birds: Patterns and processes Area sensitivity in North American grassland birds: Patterns and processes
Grassland birds have declined more than other bird groups in North America in the past 35-40 years (Vickery and Herkert 2001, Sauer et al. 2008), prompting a wide variety of research aimed at understanding these declines, as well as conservation programs trying to reverse the declines (Askins et al. 2007). Area sensitivity, whereby the pattern of a species’ occurrence and density...
Authors
C. A. Ribic, Rolf R. Koford, J.R. Herkert, Douglas H. Johnson, N.D. Niemuth, D.E. Naugle, Kristel K. Bakker, D. W. Sample, R.B. Renfrew
Influence of trees in the landscape on parasitism rates of grassland passerine nests in Southeastern North Dakota Influence of trees in the landscape on parasitism rates of grassland passerine nests in Southeastern North Dakota
Woody vegetation has been linked to increased rates of Brown-headed Cowbird (Molothrus ater) parasitism for some grassland hosts. In northern North Dakota, however, studies reported that parasitism of grassland passerine nests was lower in landscapes with trees than in those without trees. We looked for evidence of this pattern elsewhere, using data from two studies conducted on the...
Authors
Pamela J. Pietz, Deborah A. Buhl, Jill A. Shaffer, Maiken Winter, Douglas H. Johnson
Factors associated with arrival densities of grasshopper sparrow (Ammodramus savannarum) and baird's sparrow (A. bairdii) in the upper great plains Factors associated with arrival densities of grasshopper sparrow (Ammodramus savannarum) and baird's sparrow (A. bairdii) in the upper great plains
Although critical to habitat and population management, the proximate cues that birds use to establish territories are largely unknown. Understanding these cues is important for birds, such as many grassland birds, that exhibit high annual variability in population density and make new habitat-selection decisions annually. Identifying the actual cues used is difficult in the field, but...
Authors
M.A. Ahlering, Douglas H. Johnson, John Faaborg
Science and Products
Filter Total Items: 318
Influences of environmental and anthropogenic features on greater sage-grouse populations, 1997-2007 Influences of environmental and anthropogenic features on greater sage-grouse populations, 1997-2007
The Greater Sage-Grouse (Centrocercus urophasianus), endemic to western North Amer-ica, is of great conservation interest. Its popula-tions are tracked by spring counts of males at lek sites. We explored the relations between trends of Greater Sage-Grouse lek counts from 1997 to 2007 and a variety of natural and anthropogenic fea-tures. We found that trends were correlated with several...
Authors
Douglas H. Johnson, Matthew J. Holloran, John W. Connelly, Steven E. Hanser, Courtney L. Amundson, Steven T. Knick
Conserving migratory land birds in the New World: Do we know enough? Conserving migratory land birds in the New World: Do we know enough?
Migratory bird needs must be met during four phases of the year: breeding season, fall migration, wintering, and spring migration; thus, management may be needed during all four phases. The bulk of research and management has focused on the breeding season, although several issues remain unsettled, including the spatial extent of habitat influences on fitness and the importance of...
Authors
John Faaborg, Richard T. Holmes, A.D. Anders, K.L. Bildstein, K.M. Dugger, S.A. Gauthreaux, P. Heglund, K.A. Hobson, A.E. Jahn, Douglas H. Johnson, S.C. Latta, D.J. Levey, P.P. Marra, C.L. Merkord, E. Nol, S.I. Rothstein, T.W. Sherry, Sillett T. Scott, F. R. Thompson, N. Warnock
Feeding ecology of arctic-nesting sandpipers during spring migration through the prairie pothole region Feeding ecology of arctic-nesting sandpipers during spring migration through the prairie pothole region
We evaluated food habits of 4 species of spring-migrant calidrid sandpipers in the Prairie Pothole Region (PPR) of North Dakota. Sandpipers foraged in several wetland classes and fed primarily on aquatic dipterans, mostly larvae, and the midge family Chironomidae was the primary food eaten. Larger sandpiper species foraged in deeper water and took larger larvae than did smaller...
Authors
J.L. Eldridge, Gary L. Krapu, Douglas H. Johnson
Area sensitivity in North American grassland birds: Patterns and processes Area sensitivity in North American grassland birds: Patterns and processes
Grassland birds have declined more than other bird groups in North America in the past 35-40 years (Vickery and Herkert 2001, Sauer et al. 2008), prompting a wide variety of research aimed at understanding these declines, as well as conservation programs trying to reverse the declines (Askins et al. 2007). Area sensitivity, whereby the pattern of a species’ occurrence and density...
Authors
C. A. Ribic, Rolf R. Koford, J.R. Herkert, Douglas H. Johnson, N.D. Niemuth, D.E. Naugle, Kristel K. Bakker, D. W. Sample, R.B. Renfrew
Influence of trees in the landscape on parasitism rates of grassland passerine nests in Southeastern North Dakota Influence of trees in the landscape on parasitism rates of grassland passerine nests in Southeastern North Dakota
Woody vegetation has been linked to increased rates of Brown-headed Cowbird (Molothrus ater) parasitism for some grassland hosts. In northern North Dakota, however, studies reported that parasitism of grassland passerine nests was lower in landscapes with trees than in those without trees. We looked for evidence of this pattern elsewhere, using data from two studies conducted on the...
Authors
Pamela J. Pietz, Deborah A. Buhl, Jill A. Shaffer, Maiken Winter, Douglas H. Johnson
Factors associated with arrival densities of grasshopper sparrow (Ammodramus savannarum) and baird's sparrow (A. bairdii) in the upper great plains Factors associated with arrival densities of grasshopper sparrow (Ammodramus savannarum) and baird's sparrow (A. bairdii) in the upper great plains
Although critical to habitat and population management, the proximate cues that birds use to establish territories are largely unknown. Understanding these cues is important for birds, such as many grassland birds, that exhibit high annual variability in population density and make new habitat-selection decisions annually. Identifying the actual cues used is difficult in the field, but...
Authors
M.A. Ahlering, Douglas H. Johnson, John Faaborg