Douglas Johnson (Former Employee)
Science and Products
Filter Total Items: 318
Migration and habitat preferences of Swainson's Hawks at an autumn stopover site in northwestern Texas Migration and habitat preferences of Swainson's Hawks at an autumn stopover site in northwestern Texas
Unlike most raptors, the Swainson's Hawk (Buteo swainsoni) migrates long distances between breeding and wintering ranges, which elevates the importance of stopover sites for foraging. We conducted three years of fall surveys in the Southern High Plains of Texas. Migrant Swainson's Hawks moved through the area mostly between July and mid-October, peaking in September. Subadults tended to...
Authors
Carroll Littlefield, Douglas Johnson
Monitoring that matters Monitoring that matters
Monitoring is a critically important activity for assessing the status of a system, such as the health of an individual, the balance in one's checking account, profits and losses of a business, the economic activity of a nation, or the size of an animal population. Monitoring is especially vital for evaluating changes in the system associated with specific known impacts occurring to the...
Authors
Douglas Johnson
The treatment of missing data in long-term monitoring programs The treatment of missing data in long-term monitoring programs
No abstract available.
Authors
Douglas Johnson, Michael Soma
Aerial surveys adjusted by ground surveys to estimate area occupied by black-tailed prairie dog colonies Aerial surveys adjusted by ground surveys to estimate area occupied by black-tailed prairie dog colonies
Aerial surveys using line-intercept methods are one approach to estimate the extent of prairie dog colonies in a large geographic area. Although black-tailed prairie dogs (Cynomys ludovicianus) construct conspicuous mounds at burrow openings, aerial observers have difficulty discriminating between areas with burrows occupied by prairie dogs (colonies) versus areas of uninhabited burrows...
Authors
John Sidle, David J. Augustine, Douglas Johnson, Sterling Miller, Jack Cully, Richard Reading
Geographic distribution of the mid-continent population of sandhill cranes and related management applications Geographic distribution of the mid-continent population of sandhill cranes and related management applications
The Mid-continent Population (MCP) of sandhill cranes (Grus canadensis) is widely hunted in North America and is separated into the Gulf Coast Subpopulation and Western Subpopulation for management purposes. Effective harvest management of the MCP requires detailed knowledge of breeding distribution of subspecies and subpopulations, chronology of their use of fall staging areas and...
Authors
Gary Krapu, David A. Brandt, Kenneth L. Jones, Douglas Johnson
Conservation of greater sage-grouse- a synthesis of current trends and future management Conservation of greater sage-grouse- a synthesis of current trends and future management
Recent analyses of Greater Sage-Grouse (Centrocercus urophasianus) populations indicate substantial declines in many areas but relatively stable populations in other portions of the species? range. Sagebrush (Artemisia spp.) habitats neces-sary to support sage-grouse are being burned by large wildfires, invaded by nonnative plants, and developed for energy resources (gas, oil, and wind)...
Authors
John W. Connelly, Steven Knick, Clait E. Braun, William Baker, Erik Beever, Thomas Christiansen, Kevin E. Doherty, Edward Garton, Christian Hagen, Steven Hanser, Douglas Johnson, Matthias Leu, Richard F. Miller, David Naugle, Sara Oyler-McCance, David Pyke, Kerry Reese, Michael Schroeder, San Stiver, Brett Walker, Michael Wisdorn
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 Johnson, Matthew J. Holloran, John W. Connelly, Steven Hanser, Courtney Amundson, Steven 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 Holmes, A.D. Anders, K.L. Bildstein, K.M. Dugger, S.A. Gauthreaux, P. Heglund, K.A. Hobson, A.E. Jahn, Douglas Johnson, S.C. Latta, D.J. Levey, P.P. Marra, C.L. Merkord, E. Nol, S.I. Rothstein, T.W. Sherry, Sillett Scott, F. 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 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 Koford, J.R. Herkert, Douglas Johnson, N.D. Niemuth, D.E. Naugle, Kristel Bakker, D. 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 Pietz, Deborah Buhl, Jill Shaffer, Maiken Winter, Douglas 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 Johnson, John Faaborg
Science and Products
Filter Total Items: 318
Migration and habitat preferences of Swainson's Hawks at an autumn stopover site in northwestern Texas Migration and habitat preferences of Swainson's Hawks at an autumn stopover site in northwestern Texas
Unlike most raptors, the Swainson's Hawk (Buteo swainsoni) migrates long distances between breeding and wintering ranges, which elevates the importance of stopover sites for foraging. We conducted three years of fall surveys in the Southern High Plains of Texas. Migrant Swainson's Hawks moved through the area mostly between July and mid-October, peaking in September. Subadults tended to...
Authors
Carroll Littlefield, Douglas Johnson
Monitoring that matters Monitoring that matters
Monitoring is a critically important activity for assessing the status of a system, such as the health of an individual, the balance in one's checking account, profits and losses of a business, the economic activity of a nation, or the size of an animal population. Monitoring is especially vital for evaluating changes in the system associated with specific known impacts occurring to the...
Authors
Douglas Johnson
The treatment of missing data in long-term monitoring programs The treatment of missing data in long-term monitoring programs
No abstract available.
Authors
Douglas Johnson, Michael Soma
Aerial surveys adjusted by ground surveys to estimate area occupied by black-tailed prairie dog colonies Aerial surveys adjusted by ground surveys to estimate area occupied by black-tailed prairie dog colonies
Aerial surveys using line-intercept methods are one approach to estimate the extent of prairie dog colonies in a large geographic area. Although black-tailed prairie dogs (Cynomys ludovicianus) construct conspicuous mounds at burrow openings, aerial observers have difficulty discriminating between areas with burrows occupied by prairie dogs (colonies) versus areas of uninhabited burrows...
Authors
John Sidle, David J. Augustine, Douglas Johnson, Sterling Miller, Jack Cully, Richard Reading
Geographic distribution of the mid-continent population of sandhill cranes and related management applications Geographic distribution of the mid-continent population of sandhill cranes and related management applications
The Mid-continent Population (MCP) of sandhill cranes (Grus canadensis) is widely hunted in North America and is separated into the Gulf Coast Subpopulation and Western Subpopulation for management purposes. Effective harvest management of the MCP requires detailed knowledge of breeding distribution of subspecies and subpopulations, chronology of their use of fall staging areas and...
Authors
Gary Krapu, David A. Brandt, Kenneth L. Jones, Douglas Johnson
Conservation of greater sage-grouse- a synthesis of current trends and future management Conservation of greater sage-grouse- a synthesis of current trends and future management
Recent analyses of Greater Sage-Grouse (Centrocercus urophasianus) populations indicate substantial declines in many areas but relatively stable populations in other portions of the species? range. Sagebrush (Artemisia spp.) habitats neces-sary to support sage-grouse are being burned by large wildfires, invaded by nonnative plants, and developed for energy resources (gas, oil, and wind)...
Authors
John W. Connelly, Steven Knick, Clait E. Braun, William Baker, Erik Beever, Thomas Christiansen, Kevin E. Doherty, Edward Garton, Christian Hagen, Steven Hanser, Douglas Johnson, Matthias Leu, Richard F. Miller, David Naugle, Sara Oyler-McCance, David Pyke, Kerry Reese, Michael Schroeder, San Stiver, Brett Walker, Michael Wisdorn
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 Johnson, Matthew J. Holloran, John W. Connelly, Steven Hanser, Courtney Amundson, Steven 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 Holmes, A.D. Anders, K.L. Bildstein, K.M. Dugger, S.A. Gauthreaux, P. Heglund, K.A. Hobson, A.E. Jahn, Douglas Johnson, S.C. Latta, D.J. Levey, P.P. Marra, C.L. Merkord, E. Nol, S.I. Rothstein, T.W. Sherry, Sillett Scott, F. 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 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 Koford, J.R. Herkert, Douglas Johnson, N.D. Niemuth, D.E. Naugle, Kristel Bakker, D. 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 Pietz, Deborah Buhl, Jill Shaffer, Maiken Winter, Douglas 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 Johnson, John Faaborg