Douglas Johnson
Douglas Johnson is a Research Statistician (Emeritus) for the USGS Northern Prairie Wildlife Research Center in Jamestown, North Dakota.
Science and Products
Filter Total Items: 310
Changes in breeding bird populations in North Dakota: 1967 to 1992-93
We compared breeding bird populations in North Dakota using surveys conducted in 1967 and 1992-93. In decreasing order, the five most frequently occurring species were Horned Lark (Eremophila alpestris), Brown-headed Cowbird (Molothrus ater), Western Meadowlark (Sturnella neglecta), Red-winged Blackbird (Agelaius phoeniceus), and Eastern Kingbird (Tyrannus tyrannus). The five most abundant species
Authors
L.D. Igl, D. H. Johnson
North Dakota bird life: tracking changes over a quarter century
No abstract available.
Authors
D. H. Johnson, L.D. Igl, C.J. Johnson
Effects of fire on bird populations in mixed-grass prairie
The mixed-grass prairie is one of the largest ecosystems in North America, originally covering about 69 million ha (Bragg and Steuter 1995). Although much of the natural vegetation has been replaced by cropland and other uses (Samson and Knopf 1994, Bragg and Steuter 1995), significant areas have been preserved in national wildlife refuges, waterfowl production areas, state game management areas,
Authors
Douglas H. Johnson
An introduction to the Woodworth Study Area
The Woodworth Study Area (WSA) was purchased by the U.S. Fish and Wildlife Service (FWS) during the early 1960's as a waterfowl production area. Unlike most such areas, its primary purpose was not to provide waterfowl breeding habitat directly, but instead it was dedicated for use as a research area to develop information for better management of upland and wetland habitats. This article provide
Authors
Douglas H. Johnson, Kenneth F. Higgins, Robert O. Woodward
Management of northern prairies and wetlands for the conservation of neotropical migratory birds
Grasslands and wetlands of the northern prairies provide important breeding habitat for a number of birds. Deciding which species deserve most attention in managing those habitats depends, in part, on the importance of the area to the species. Many species in northern prairies are more common elsewhere and need no special consideration in that area. Several species, however, are critically depende
Authors
Douglas H. Johnson
Survival of radiomarked canvasback ducklings in northwestern Minnesota
Duckling survival, an important factor affecting annual recruitment, has not been determined adequately for canvasbacks (Aythya valisineria). We investigated the magnitude, timing, and causes of mortality of canvasback ducklings from hatch to fledging at the Agassiz National Wildlife Refuge (NWR) in northwestern Minnesota during 1987-90. During the 4 years, 217 day-old ducklings were radiomarke
Authors
Carl E. Korschgen, Kevin P. Kenow, William L. Green, Douglas H. Johnson, Michael D. Samuel, Louis Sileo
Survival of radiomarked canvasback ducklings in northwestern Minnesota
Duckling survival, an important factor affecting annual recruitment, has not been determined adequately for canvasbacks (Aythya valisineria). We investigated the magnitude, timing, and causes of mortality of canvasback ducklings from hatch to fledging at the Agassiz National Wildlife Refuge (NWR) in northwestern Minnesota during 1987-90. During the 4 years, 217 day-old ducklings were radiomarked a
Authors
Carl E. Korschgen, Kevin P. Kenow, William L. Green, Douglas H. Johnson
Waterfowl communities in the northern plains: Chapter 13
Features that determine the composition of avian communities have received extensive and enthusiastic attention, both empirically and theoretically (e.g., Cody 1974; Strong et al. 1984; Wiens, 1989a,b). Interspecific competition for limited resources is one influence widely regarded as critical, but others include species-specific responses to environmental conditions, predation, parasitism, comme
Authors
Douglas H. Johnson
Long-term declines in nest success of prairie ducks
Increased predation on nests of ducks in prairie uplands, as a result of habitat alteration, has been hypothesized to cause decreased nest success and population sizes. We tested whether, and by how much, nest success declined using data compiled from 37 studies conducted between 1935 and 1992 at 67 sites in the Prairie Pothole Region of Canada and the United States. Nest success declined (P = 0.0
Authors
W.D. Beauchamp, Rolf R. Koford, T.D. Nudds, R. Clark, D. H. Johnson
Using known populations of pronghorn to evaluate sampling plans and estimators
Although sampling plans and estimators of abundance have good theoretical properties, their performance in real situations is rarely assessed because true population sizes are unknown. We evaluated widely used sampling plans and estimators of population size on 3 known clustered distributions of pronghorn (Antilocapra americana). Our criteria were accuracy of the estimate, coverage of 95% confiden
Authors
K.M. Kraft, D. H. Johnson, J.M. Samuelson, S.H. Allen
Statistical sirens: The allure of nonparametrics
Although nonparametric statistical methods have a role to play in the analysis of data, often their virtues are overstated and their deficiencies overlooked. A recent Special Feature in Ecology advocated nonparametric methods because of an erroneously stated advantage that they require no assumptions regarding the distribution underlying the observations. The present paper points out some often—ig
Authors
Douglas H. Johnson
Factors associated with duck nest success in the prairie pothole region of Canada
Populations of some dabbling ducks have declined sharply in recent decades and information is needed to understand reasons for this. During 1982-85, we studied duck nesting for 1-4 years in 17 1.6 by 16.0-km, high-density duck areas in the Prairie Pothole Region (PPR) of Canada, 9 in parkland and 8 in prairie. We estimated nest-initiation dates, habitat preferences, nest success, and nest fates fo
Authors
Raymond J. Greenwood, Alan B. Sargeant, Douglas H. Johnson, Lewis M. Cowardin, Terry L. Shaffer
Science and Products
Filter Total Items: 310
Changes in breeding bird populations in North Dakota: 1967 to 1992-93
We compared breeding bird populations in North Dakota using surveys conducted in 1967 and 1992-93. In decreasing order, the five most frequently occurring species were Horned Lark (Eremophila alpestris), Brown-headed Cowbird (Molothrus ater), Western Meadowlark (Sturnella neglecta), Red-winged Blackbird (Agelaius phoeniceus), and Eastern Kingbird (Tyrannus tyrannus). The five most abundant species
Authors
L.D. Igl, D. H. Johnson
North Dakota bird life: tracking changes over a quarter century
No abstract available.
Authors
D. H. Johnson, L.D. Igl, C.J. Johnson
Effects of fire on bird populations in mixed-grass prairie
The mixed-grass prairie is one of the largest ecosystems in North America, originally covering about 69 million ha (Bragg and Steuter 1995). Although much of the natural vegetation has been replaced by cropland and other uses (Samson and Knopf 1994, Bragg and Steuter 1995), significant areas have been preserved in national wildlife refuges, waterfowl production areas, state game management areas,
Authors
Douglas H. Johnson
An introduction to the Woodworth Study Area
The Woodworth Study Area (WSA) was purchased by the U.S. Fish and Wildlife Service (FWS) during the early 1960's as a waterfowl production area. Unlike most such areas, its primary purpose was not to provide waterfowl breeding habitat directly, but instead it was dedicated for use as a research area to develop information for better management of upland and wetland habitats. This article provide
Authors
Douglas H. Johnson, Kenneth F. Higgins, Robert O. Woodward
Management of northern prairies and wetlands for the conservation of neotropical migratory birds
Grasslands and wetlands of the northern prairies provide important breeding habitat for a number of birds. Deciding which species deserve most attention in managing those habitats depends, in part, on the importance of the area to the species. Many species in northern prairies are more common elsewhere and need no special consideration in that area. Several species, however, are critically depende
Authors
Douglas H. Johnson
Survival of radiomarked canvasback ducklings in northwestern Minnesota
Duckling survival, an important factor affecting annual recruitment, has not been determined adequately for canvasbacks (Aythya valisineria). We investigated the magnitude, timing, and causes of mortality of canvasback ducklings from hatch to fledging at the Agassiz National Wildlife Refuge (NWR) in northwestern Minnesota during 1987-90. During the 4 years, 217 day-old ducklings were radiomarke
Authors
Carl E. Korschgen, Kevin P. Kenow, William L. Green, Douglas H. Johnson, Michael D. Samuel, Louis Sileo
Survival of radiomarked canvasback ducklings in northwestern Minnesota
Duckling survival, an important factor affecting annual recruitment, has not been determined adequately for canvasbacks (Aythya valisineria). We investigated the magnitude, timing, and causes of mortality of canvasback ducklings from hatch to fledging at the Agassiz National Wildlife Refuge (NWR) in northwestern Minnesota during 1987-90. During the 4 years, 217 day-old ducklings were radiomarked a
Authors
Carl E. Korschgen, Kevin P. Kenow, William L. Green, Douglas H. Johnson
Waterfowl communities in the northern plains: Chapter 13
Features that determine the composition of avian communities have received extensive and enthusiastic attention, both empirically and theoretically (e.g., Cody 1974; Strong et al. 1984; Wiens, 1989a,b). Interspecific competition for limited resources is one influence widely regarded as critical, but others include species-specific responses to environmental conditions, predation, parasitism, comme
Authors
Douglas H. Johnson
Long-term declines in nest success of prairie ducks
Increased predation on nests of ducks in prairie uplands, as a result of habitat alteration, has been hypothesized to cause decreased nest success and population sizes. We tested whether, and by how much, nest success declined using data compiled from 37 studies conducted between 1935 and 1992 at 67 sites in the Prairie Pothole Region of Canada and the United States. Nest success declined (P = 0.0
Authors
W.D. Beauchamp, Rolf R. Koford, T.D. Nudds, R. Clark, D. H. Johnson
Using known populations of pronghorn to evaluate sampling plans and estimators
Although sampling plans and estimators of abundance have good theoretical properties, their performance in real situations is rarely assessed because true population sizes are unknown. We evaluated widely used sampling plans and estimators of population size on 3 known clustered distributions of pronghorn (Antilocapra americana). Our criteria were accuracy of the estimate, coverage of 95% confiden
Authors
K.M. Kraft, D. H. Johnson, J.M. Samuelson, S.H. Allen
Statistical sirens: The allure of nonparametrics
Although nonparametric statistical methods have a role to play in the analysis of data, often their virtues are overstated and their deficiencies overlooked. A recent Special Feature in Ecology advocated nonparametric methods because of an erroneously stated advantage that they require no assumptions regarding the distribution underlying the observations. The present paper points out some often—ig
Authors
Douglas H. Johnson
Factors associated with duck nest success in the prairie pothole region of Canada
Populations of some dabbling ducks have declined sharply in recent decades and information is needed to understand reasons for this. During 1982-85, we studied duck nesting for 1-4 years in 17 1.6 by 16.0-km, high-density duck areas in the Prairie Pothole Region (PPR) of Canada, 9 in parkland and 8 in prairie. We estimated nest-initiation dates, habitat preferences, nest success, and nest fates fo
Authors
Raymond J. Greenwood, Alan B. Sargeant, Douglas H. Johnson, Lewis M. Cowardin, Terry L. Shaffer