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
Age determination of mallards
A technique for distinguishing adult from yearling wild mallards (Anas platyrhynchos), from late winter through the nesting season, was developed by applying discriminant analysis procedures to selected wing feather characters of 126 yearlings and 76 adults (2-year-olds) hand-reared from wild eggs during 1974, 1975, and 1977. Average values for feather characters generally increased as the birds a
Authors
G.L. Krapu, D. H. Johnson, C.W. Dane
Mathematics and mallard management
Waterfowl managers can effectively use simple population models to aid in making management decisions. We present a basic model of the change in population size as related to survival and recruitment. A management technique designed to increase survival of mallards (Anas platyrhynchos) by limiting harvest on the Chippewa National Forest, Minnesota, is used to illustrate the application of models i
Authors
L.M. Cowardin, D. H. Johnson
Breeding bird populations of selected grasslands in east central North Dakota -- 1977 - Kentucky blue grass prairie and mixed prairie I-V, VIII
Abstract has not been submitted
Authors
D. H. Johnson
Interpreting the results of nesting studies
Nesting studies are used to assess the production of birds and to evaluate nesting habitats. Most such studies involve finding nests in a given area and subsequently determining the proportion that hatched. Unfortunately, the results are often biased by unrecognized differences in the probabilities of finding successful and unsuccessful nests. The observed hatch rates of 1,900 nests of blue-winged
Authors
H.W. Miller, D. H. Johnson
Some Bayesian statistical techniques useful in estimating frequency and density
This paper presents some elementary applications of Bayesian statistics to problems faced by wildlife biologists. Bayesian confidence limits for frequency of occurrence are shown to be generally superior to classical confidence limits. Population density can be estimated from frequency data if the species is sparsely distributed relative to the size of the sample plot. For other situations, limits
Authors
D. H. Johnson
Some Bayesian statistical techniques useful in estimating frequency and density
No abstract available.
Authors
Douglas H. Johnson
Impact of red fox predation on the sex ratio of prairie mallards
No abstract available.
Authors
Douglas H. Johnson, Alan B. Sargeant
Impact of red fox predation on the sex ratio of prairie mallards
No abstract available.
Authors
D. H. Johnson, A. B. Sargeant
Breeding bird populations of selected grasslands in east central North Dakota -- 1976 - Kentucky blue grass prairie and mixed prairie I-V
Abstract has not been submitted
Authors
D. H. Johnson
Book Review: Minnesota's birds: where, when and how many by Janet C. Green and Robert B. Janssen
No abstract available.
Authors
D. H. Johnson
[Book review] One Time Harvest: Reflections on Coal and our Future, by Mike Jacobs
Review of: One time harvest: reflections on coal and our future. Mike Jacobs. 1975. Indiana University. 300 p.
Authors
D. H. Johnson
Science and Products
Filter Total Items: 310
Age determination of mallards
A technique for distinguishing adult from yearling wild mallards (Anas platyrhynchos), from late winter through the nesting season, was developed by applying discriminant analysis procedures to selected wing feather characters of 126 yearlings and 76 adults (2-year-olds) hand-reared from wild eggs during 1974, 1975, and 1977. Average values for feather characters generally increased as the birds a
Authors
G.L. Krapu, D. H. Johnson, C.W. Dane
Mathematics and mallard management
Waterfowl managers can effectively use simple population models to aid in making management decisions. We present a basic model of the change in population size as related to survival and recruitment. A management technique designed to increase survival of mallards (Anas platyrhynchos) by limiting harvest on the Chippewa National Forest, Minnesota, is used to illustrate the application of models i
Authors
L.M. Cowardin, D. H. Johnson
Breeding bird populations of selected grasslands in east central North Dakota -- 1977 - Kentucky blue grass prairie and mixed prairie I-V, VIII
Abstract has not been submitted
Authors
D. H. Johnson
Interpreting the results of nesting studies
Nesting studies are used to assess the production of birds and to evaluate nesting habitats. Most such studies involve finding nests in a given area and subsequently determining the proportion that hatched. Unfortunately, the results are often biased by unrecognized differences in the probabilities of finding successful and unsuccessful nests. The observed hatch rates of 1,900 nests of blue-winged
Authors
H.W. Miller, D. H. Johnson
Some Bayesian statistical techniques useful in estimating frequency and density
This paper presents some elementary applications of Bayesian statistics to problems faced by wildlife biologists. Bayesian confidence limits for frequency of occurrence are shown to be generally superior to classical confidence limits. Population density can be estimated from frequency data if the species is sparsely distributed relative to the size of the sample plot. For other situations, limits
Authors
D. H. Johnson
Some Bayesian statistical techniques useful in estimating frequency and density
No abstract available.
Authors
Douglas H. Johnson
Impact of red fox predation on the sex ratio of prairie mallards
No abstract available.
Authors
Douglas H. Johnson, Alan B. Sargeant
Impact of red fox predation on the sex ratio of prairie mallards
No abstract available.
Authors
D. H. Johnson, A. B. Sargeant
Breeding bird populations of selected grasslands in east central North Dakota -- 1976 - Kentucky blue grass prairie and mixed prairie I-V
Abstract has not been submitted
Authors
D. H. Johnson
Book Review: Minnesota's birds: where, when and how many by Janet C. Green and Robert B. Janssen
No abstract available.
Authors
D. H. Johnson
[Book review] One Time Harvest: Reflections on Coal and our Future, by Mike Jacobs
Review of: One time harvest: reflections on coal and our future. Mike Jacobs. 1975. Indiana University. 300 p.
Authors
D. H. Johnson