Douglas Johnson (Former Employee)
Science and Products
Filter Total Items: 318
The role of heterogeneity in animal population dynamics The role of heterogeneity in animal population dynamics
No abstract available.
Authors
Douglas H. Johnson, K.P. Burnham, J.D. Nichols
An evaluation of condition indices for birds 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...
Authors
Douglas H. Johnson, Gary L. Krapu, Kenneth J. Reinecke, Dennis G. Jorde
Evaluation of marked-recapture for estimating striped skunk abundance 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...
Authors
Raymond J. Greenwood, Alan B. Sargeant, Douglas H. Johnson
Quick estimates of success rates of duck nests Quick estimates of success rates of duck nests
Abstract has not been submitted
Authors
Douglas H. Johnson, A.T. Klett
The need for accuracy in modelling: An example 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...
Authors
Douglas H. Johnson, Michael J. Conroy, James D. Nichols
The need for accuracy in modelling: An example 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...
Authors
Douglas H. Johnson, M.J. Conroy, J.D. Nichols
Science and Products
Filter Total Items: 318
The role of heterogeneity in animal population dynamics The role of heterogeneity in animal population dynamics
No abstract available.
Authors
Douglas H. Johnson, K.P. Burnham, J.D. Nichols
An evaluation of condition indices for birds 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...
Authors
Douglas H. Johnson, Gary L. Krapu, Kenneth J. Reinecke, Dennis G. Jorde
Evaluation of marked-recapture for estimating striped skunk abundance 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...
Authors
Raymond J. Greenwood, Alan B. Sargeant, Douglas H. Johnson
Quick estimates of success rates of duck nests Quick estimates of success rates of duck nests
Abstract has not been submitted
Authors
Douglas H. Johnson, A.T. Klett
The need for accuracy in modelling: An example 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...
Authors
Douglas H. Johnson, Michael J. Conroy, James D. Nichols
The need for accuracy in modelling: An example 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...
Authors
Douglas H. Johnson, M.J. Conroy, J.D. Nichols