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
An empirical Bayes approach to analyzing recurring animal surveys
Recurring estimates of the size of animal populations are often required by biologists of wildlife managers. Because of cost or other constraints, estimates frequently lack the accuracy desired but cannot readily be improved by additional sampling. This report proposes a statistical method employing empirical Bayes (EB) estimators as alternatives to those customarily used to estimate population si
Authors
D. H. Johnson
Least squares estimation of avian molt rates
A straightforward least squares method of estimating the rate at which birds molt feathers is presented, suitable for birds captured more than once during the period of molt. The date of molt onset can also be estimated. The method is applied to male and female mourning doves.
Authors
D. H. Johnson
Importance of individual species of predators on nesting success of ducks in the Canadian prairie pothole region
We followed 3094 upland nests of several species of ducks. Clutches in most nests were lost to predation. We related daily nest predation rates to indices of activity of eight egg-eating predators, precipitation during the nesting season, and measures of wetland conditions. Activity indices of red fox (Vulpes vulpes), striped skunk (Mephitis mephitis), and raccoon (Procyon lotor) activity were pos
Authors
Douglas H. Johnson, Alan B. Sargeant, Raymond J. Greenwood
Determinants of breeding distributions of ducks
The settling of breeding habitat by migratory waterfowl is a topic of both theoretical and practical interest. We use the results of surveys conducted annually during 1955-81 in major breeding areas to examine the factors that affect the distributions of 10 common North American duck species. Three patterns of settling are described: homing, opportunistic, and flexible. Homing is generally more pr
Authors
D. H. Johnson, J.W. Grier
Size differences in migrant sandpiper flocks: ghosts in ephemeral guilds
Scolopacid sandpipers were studied from 1980 until 1984 during spring migration in North Dakota. Common species foraging together in mixed-species flocks differed in bill length most often by 20 to 30 percent (ratios from 1.2:1 to 1.3:1). Observed flocks were compared to computer generated flocks drawn from three source pools of Arctic-nesting sandpipers. The source pools included 51 migrant speci
Authors
J.L. Eldridge, D. H. Johnson
Workshop summary: Hunting vulnerability and mortality
No abstract available.
Authors
F. Montalbano, D. H. Johnson, M. R. Miller, D. H. Rusch
Some considerations in modeling the mallard life cycle
We outline a population model proposed to accommodate the full life cycle of the mallard (Anas platyrhynchos). Events during the breeding season are better understood than events at other times of the year, but recent findings suggest the importance of phenomena away from the breeding grounds. Several processes are discussed relative to mallard population dynamics. Compensatory mortality is a poor
Authors
D. H. Johnson, J. D. Nichols, M.J. Conroy, L.M. Cowardin
Duck nest success in the prairie pothole region
We estimated nest success of mallard (Anas platyrhynchos), gadwall (A. strepera), blue-winged teal (A. discors), northern shoveler (A. clypeata), and northern pintail (A. acuta) for 5 regions in North Dakota, South Dakota, and Minnesota, for 1-3 periods between 1966 and 1984, and for 8 habitat classes. We obtained composite estimates of nest success for regions and periods by weighting each habita
Authors
A.T. Klett, T.L. Shaffer, D. H. Johnson
[Book Review] Building Models for Conservation and Wildlife Management, by A. M. Starfield and A. L. Bleloch
Review of: Building Models for Conservation and Wildlife Management. By Anthony Starfield and A. L. Bleloch. New York: Macmillan; London: Collier Macmillan, 1986. ISBN: 002948040X. xi, 253 p.: ill.; 25 cm.
Authors
D. H. Johnson
Applications of a simulation model to decisions in mallard management
A system comprising simulation models and data bases for habitat availability and nest success rates was used to predict results from a mallard (Anas platyrhynchos) management plan and to compare six management methods with a control. Individual treatments in the applications included land purchase for waterfowl production, wetland easement purchase, lease of uplands for waterfowl management, crop
Authors
L.M. Cowardin, D. H. Johnson, T.L. Shaffer, D. W. Sparling
Some considerations in modeling the mallard life cycle
We outline a population model proposed to accommodate the full life cycle of the mallard (Anas platyrhynchos}. Events during the breeding season are better understood than events at other times of the year, but recent findings suggest the importance of phenomena away from the breeding grounds. Several processes are discussed relative to mallard population dynamics. Compensatory mortality is a poor
Authors
D. H. Johnson, J. D. Nichols, M.J. Conroy, L.M. Cowardin
[Book review] Statistics in ornithology, edited by B. J. T. Morgan and P. M. North
Review of: Statistics in Ornithology. B. J. T. Morgan and P. M. North (eds.). Berlin: Springer-Verlag, 1985. xxv + 418 pp. $29.60 (paperback).
Authors
D. H. Johnson
Science and Products
Filter Total Items: 310
An empirical Bayes approach to analyzing recurring animal surveys
Recurring estimates of the size of animal populations are often required by biologists of wildlife managers. Because of cost or other constraints, estimates frequently lack the accuracy desired but cannot readily be improved by additional sampling. This report proposes a statistical method employing empirical Bayes (EB) estimators as alternatives to those customarily used to estimate population si
Authors
D. H. Johnson
Least squares estimation of avian molt rates
A straightforward least squares method of estimating the rate at which birds molt feathers is presented, suitable for birds captured more than once during the period of molt. The date of molt onset can also be estimated. The method is applied to male and female mourning doves.
Authors
D. H. Johnson
Importance of individual species of predators on nesting success of ducks in the Canadian prairie pothole region
We followed 3094 upland nests of several species of ducks. Clutches in most nests were lost to predation. We related daily nest predation rates to indices of activity of eight egg-eating predators, precipitation during the nesting season, and measures of wetland conditions. Activity indices of red fox (Vulpes vulpes), striped skunk (Mephitis mephitis), and raccoon (Procyon lotor) activity were pos
Authors
Douglas H. Johnson, Alan B. Sargeant, Raymond J. Greenwood
Determinants of breeding distributions of ducks
The settling of breeding habitat by migratory waterfowl is a topic of both theoretical and practical interest. We use the results of surveys conducted annually during 1955-81 in major breeding areas to examine the factors that affect the distributions of 10 common North American duck species. Three patterns of settling are described: homing, opportunistic, and flexible. Homing is generally more pr
Authors
D. H. Johnson, J.W. Grier
Size differences in migrant sandpiper flocks: ghosts in ephemeral guilds
Scolopacid sandpipers were studied from 1980 until 1984 during spring migration in North Dakota. Common species foraging together in mixed-species flocks differed in bill length most often by 20 to 30 percent (ratios from 1.2:1 to 1.3:1). Observed flocks were compared to computer generated flocks drawn from three source pools of Arctic-nesting sandpipers. The source pools included 51 migrant speci
Authors
J.L. Eldridge, D. H. Johnson
Workshop summary: Hunting vulnerability and mortality
No abstract available.
Authors
F. Montalbano, D. H. Johnson, M. R. Miller, D. H. Rusch
Some considerations in modeling the mallard life cycle
We outline a population model proposed to accommodate the full life cycle of the mallard (Anas platyrhynchos). Events during the breeding season are better understood than events at other times of the year, but recent findings suggest the importance of phenomena away from the breeding grounds. Several processes are discussed relative to mallard population dynamics. Compensatory mortality is a poor
Authors
D. H. Johnson, J. D. Nichols, M.J. Conroy, L.M. Cowardin
Duck nest success in the prairie pothole region
We estimated nest success of mallard (Anas platyrhynchos), gadwall (A. strepera), blue-winged teal (A. discors), northern shoveler (A. clypeata), and northern pintail (A. acuta) for 5 regions in North Dakota, South Dakota, and Minnesota, for 1-3 periods between 1966 and 1984, and for 8 habitat classes. We obtained composite estimates of nest success for regions and periods by weighting each habita
Authors
A.T. Klett, T.L. Shaffer, D. H. Johnson
[Book Review] Building Models for Conservation and Wildlife Management, by A. M. Starfield and A. L. Bleloch
Review of: Building Models for Conservation and Wildlife Management. By Anthony Starfield and A. L. Bleloch. New York: Macmillan; London: Collier Macmillan, 1986. ISBN: 002948040X. xi, 253 p.: ill.; 25 cm.
Authors
D. H. Johnson
Applications of a simulation model to decisions in mallard management
A system comprising simulation models and data bases for habitat availability and nest success rates was used to predict results from a mallard (Anas platyrhynchos) management plan and to compare six management methods with a control. Individual treatments in the applications included land purchase for waterfowl production, wetland easement purchase, lease of uplands for waterfowl management, crop
Authors
L.M. Cowardin, D. H. Johnson, T.L. Shaffer, D. W. Sparling
Some considerations in modeling the mallard life cycle
We outline a population model proposed to accommodate the full life cycle of the mallard (Anas platyrhynchos}. Events during the breeding season are better understood than events at other times of the year, but recent findings suggest the importance of phenomena away from the breeding grounds. Several processes are discussed relative to mallard population dynamics. Compensatory mortality is a poor
Authors
D. H. Johnson, J. D. Nichols, M.J. Conroy, L.M. Cowardin
[Book review] Statistics in ornithology, edited by B. J. T. Morgan and P. M. North
Review of: Statistics in Ornithology. B. J. T. Morgan and P. M. North (eds.). Berlin: Springer-Verlag, 1985. xxv + 418 pp. $29.60 (paperback).
Authors
D. H. Johnson