Douglas Johnson (Former Employee)
Science and Products
Filter Total Items: 318
Determinants of breeding distributions of ducks 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...
Authors
Douglas H. Johnson, J.W. Grier
[Book Review] Building Models for Conservation and Wildlife Management, by A. M. Starfield and A. L. Bleloch [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
Douglas H. Johnson
Some considerations in modeling the mallard life cycle 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...
Authors
Douglas H. Johnson, J.D. Nichols, M.J. Conroy, L.M. Cowardin
Workshop summary: Hunting vulnerability and mortality Workshop summary: Hunting vulnerability and mortality
No abstract available.
Authors
Frank Montalbano, Douglas H. Johnson, M. R. Miller, D. H. Rusch
Some considerations in modeling the mallard life cycle 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...
Authors
Douglas H. Johnson, J.D. Nichols, M.J. Conroy, L.M. Cowardin
Applications of a simulation model to decisions in mallard management 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...
Authors
L.M. Cowardin, Douglas H. Johnson, T.L. Shaffer, D. W. Sparling
A model of the productivity of the mallard duck A model of the productivity of the mallard duck
This paper describes a stochastic computer model that simulates recruitment of the mallard (Anas platyrhynchos) under different habitat conditions and management scenarios. The model incorporates several environmental phenomena and biological relations that affect mallard recruitment. Major events include arrival of mallards in the spring, daily survival of hens, initiation of nests...
Authors
Douglas H. Johnson, Donald W. Sparling, Lewis M. Cowardin
Are mallards declining in North America? Are mallards declining in North America?
No abstract available.
Authors
Douglas H. Johnson, T.L. Shaffer
[Book review] Statistics in ornithology, edited by B. J. T. Morgan and P. M. North [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
Douglas H. Johnson
[Book review] The encyclopedia of birds, by Christopher M. Perrins and Alex L. A. Middleton [Book review] The encyclopedia of birds, by Christopher M. Perrins and Alex L. A. Middleton
Review of: The Encyclopedia of birds. Perrins, Christopher M.; Middleton, Alex L.A. New York, Facts on File, 1985. 463 p., illus. ISBN: 0-8160-1150-8.
Authors
Douglas H. Johnson
Evaluation of a mallard productivity model Evaluation of a mallard productivity model
A stochastic model of mallard (Anas platyrhynchos) productivity has been developed over a 10-year period and successfully applied to several management questions. Here we review the model and describe some recent uses and improvements that increase its realism and applicability, including naturally occurring changes in wetland habitat, catastrophic weather events, and the migrational...
Authors
Douglas H. Johnson, L.M. Cowardin, D. W. Sparling
Empirical Bayes estimates of duck population Empirical Bayes estimates of duck population
No abstract available.
Authors
Douglas H. Johnson
Science and Products
Filter Total Items: 318
Determinants of breeding distributions of ducks 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...
Authors
Douglas H. Johnson, J.W. Grier
[Book Review] Building Models for Conservation and Wildlife Management, by A. M. Starfield and A. L. Bleloch [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
Douglas H. Johnson
Some considerations in modeling the mallard life cycle 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...
Authors
Douglas H. Johnson, J.D. Nichols, M.J. Conroy, L.M. Cowardin
Workshop summary: Hunting vulnerability and mortality Workshop summary: Hunting vulnerability and mortality
No abstract available.
Authors
Frank Montalbano, Douglas H. Johnson, M. R. Miller, D. H. Rusch
Some considerations in modeling the mallard life cycle 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...
Authors
Douglas H. Johnson, J.D. Nichols, M.J. Conroy, L.M. Cowardin
Applications of a simulation model to decisions in mallard management 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...
Authors
L.M. Cowardin, Douglas H. Johnson, T.L. Shaffer, D. W. Sparling
A model of the productivity of the mallard duck A model of the productivity of the mallard duck
This paper describes a stochastic computer model that simulates recruitment of the mallard (Anas platyrhynchos) under different habitat conditions and management scenarios. The model incorporates several environmental phenomena and biological relations that affect mallard recruitment. Major events include arrival of mallards in the spring, daily survival of hens, initiation of nests...
Authors
Douglas H. Johnson, Donald W. Sparling, Lewis M. Cowardin
Are mallards declining in North America? Are mallards declining in North America?
No abstract available.
Authors
Douglas H. Johnson, T.L. Shaffer
[Book review] Statistics in ornithology, edited by B. J. T. Morgan and P. M. North [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
Douglas H. Johnson
[Book review] The encyclopedia of birds, by Christopher M. Perrins and Alex L. A. Middleton [Book review] The encyclopedia of birds, by Christopher M. Perrins and Alex L. A. Middleton
Review of: The Encyclopedia of birds. Perrins, Christopher M.; Middleton, Alex L.A. New York, Facts on File, 1985. 463 p., illus. ISBN: 0-8160-1150-8.
Authors
Douglas H. Johnson
Evaluation of a mallard productivity model Evaluation of a mallard productivity model
A stochastic model of mallard (Anas platyrhynchos) productivity has been developed over a 10-year period and successfully applied to several management questions. Here we review the model and describe some recent uses and improvements that increase its realism and applicability, including naturally occurring changes in wetland habitat, catastrophic weather events, and the migrational...
Authors
Douglas H. Johnson, L.M. Cowardin, D. W. Sparling
Empirical Bayes estimates of duck population Empirical Bayes estimates of duck population
No abstract available.
Authors
Douglas H. Johnson