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: 311
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, selection of
Authors
Douglas H. Johnson, Donald W. Sparling, Lewis 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
The role of heterogeneity in animal population dynamics
No abstract available.
Authors
D. H. Johnson, K.P. Burnham, J. D. Nichols
[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
D. H. Johnson
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 homing of mal
Authors
D. H. Johnson, L.M. Cowardin, D. W. Sparling
Evaluation of marked-recapture for estimating striped skunk abundance
The mark-recapture method for estimating striped skunk (Mephitis mephitis) abundance was evaluated by systematically livetrapping a radio-equipped population on a 31.4-km2 study area in North Dakota during late April of 1977 and 1978. The study population was 10 females and 13 males in 1977 and 20 females and 8 males in 1978. Skunks were almost exclusively nocturnal. Males traveled greater nightly
Authors
R. J. Greenwood, A. B. Sargeant, D. H. Johnson
An evaluation of condition indices for birds
A Lipid Index, the ratio of fat to fat-free dry weight, is proposed as a measure of fat stores in birds. The estimation of the index from field measurements of live birds is illustrated with data on the sandhill crane (Grus canadensis) and greater white-fronted goose (Anser albifrons). Of the various methods of assessing fat stores, lipid extraction is the most accurate but also the most involved.
Authors
D. H. Johnson, G.L. Krapu, K. J. Reinecke, Dennis G. Jorde
Quick estimates of success rates of duck nests
Abstract has not been submitted
Authors
D. H. Johnson, A.T. Klett
The need for accuracy in modelling: An example
The need for accurate information in modelling depends on the objectives of the effort, but trustworthy data are essential for a model intended for use in the management of natural resources. This point is illustrated by referring to a recently published model of canvasback ducks. We demonstrate that several key assumptions are not supported by biological evidence, and that inferences drawn from t
Authors
Douglas H. Johnson, Michael J. Conroy, James D. Nichols
The need for accuracy in modelling: An example
The need for accurate information in modelling depends on the objectives of the effort. but trustworthy data are essential for a model intended for use in the management of natural resources. This point is illustrated by referring to a recently published model of canvasback ducks. We demonstrate that several key assumptions are not supported by biological evidence, and that inferences drawn from t
Authors
D. H. Johnson, M.J. Conroy, J. D. Nichols
Science and Products
Filter Total Items: 311
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, selection of
Authors
Douglas H. Johnson, Donald W. Sparling, Lewis 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
The role of heterogeneity in animal population dynamics
No abstract available.
Authors
D. H. Johnson, K.P. Burnham, J. D. Nichols
[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
D. H. Johnson
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 homing of mal
Authors
D. H. Johnson, L.M. Cowardin, D. W. Sparling
Evaluation of marked-recapture for estimating striped skunk abundance
The mark-recapture method for estimating striped skunk (Mephitis mephitis) abundance was evaluated by systematically livetrapping a radio-equipped population on a 31.4-km2 study area in North Dakota during late April of 1977 and 1978. The study population was 10 females and 13 males in 1977 and 20 females and 8 males in 1978. Skunks were almost exclusively nocturnal. Males traveled greater nightly
Authors
R. J. Greenwood, A. B. Sargeant, D. H. Johnson
An evaluation of condition indices for birds
A Lipid Index, the ratio of fat to fat-free dry weight, is proposed as a measure of fat stores in birds. The estimation of the index from field measurements of live birds is illustrated with data on the sandhill crane (Grus canadensis) and greater white-fronted goose (Anser albifrons). Of the various methods of assessing fat stores, lipid extraction is the most accurate but also the most involved.
Authors
D. H. Johnson, G.L. Krapu, K. J. Reinecke, Dennis G. Jorde
Quick estimates of success rates of duck nests
Abstract has not been submitted
Authors
D. H. Johnson, A.T. Klett
The need for accuracy in modelling: An example
The need for accurate information in modelling depends on the objectives of the effort, but trustworthy data are essential for a model intended for use in the management of natural resources. This point is illustrated by referring to a recently published model of canvasback ducks. We demonstrate that several key assumptions are not supported by biological evidence, and that inferences drawn from t
Authors
Douglas H. Johnson, Michael J. Conroy, James D. Nichols
The need for accuracy in modelling: An example
The need for accurate information in modelling depends on the objectives of the effort. but trustworthy data are essential for a model intended for use in the management of natural resources. This point is illustrated by referring to a recently published model of canvasback ducks. We demonstrate that several key assumptions are not supported by biological evidence, and that inferences drawn from t
Authors
D. H. Johnson, M.J. Conroy, J. D. Nichols