Douglas Johnson (Former Employee)
Science and Products
Filter Total Items: 318
Forty-third breeding bird census [On selected prairies in east-central North Dakota -- 1979 - Kentucky blue grass prairie and mixed prairie I-V, VIII Forty-third breeding bird census [On selected prairies in east-central North Dakota -- 1979 - Kentucky blue grass prairie and mixed prairie I-V, VIII
Abstract has not been submitted
Authors
Douglas H. Johnson, J.M. Callow
Age determination of mallards 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...
Authors
Gary L. Krapu, Douglas H. Johnson, C.W. Dane
Modeling sandhill crane population dynamics Modeling sandhill crane population dynamics
The impact of sport hunting on the Central Flyway population of sandhill cranes (Grus canadensis) has been a subject of controversy for several years. A recent study (Buller 1979) presented new and important information on sandhill crane population dynamics. The present report is intended to incorporate that and other information into a mathematical model for the purpose of assessing the...
Authors
Douglas H. Johnson
Mathematics and mallard management 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...
Authors
L.M. Cowardin, Douglas H. Johnson
Forty-second breeding bird census - mixed prairie I-V and VIII Forty-second breeding bird census - mixed prairie I-V and VIII
Abstract has not been submitted
Authors
Douglas H. Johnson
Forty-second breeding bird census - Kentucky blue grass prairie Forty-second breeding bird census - Kentucky blue grass prairie
Abstract has not been submitted
Authors
Douglas H. Johnson
Science and Products
Filter Total Items: 318
Forty-third breeding bird census [On selected prairies in east-central North Dakota -- 1979 - Kentucky blue grass prairie and mixed prairie I-V, VIII Forty-third breeding bird census [On selected prairies in east-central North Dakota -- 1979 - Kentucky blue grass prairie and mixed prairie I-V, VIII
Abstract has not been submitted
Authors
Douglas H. Johnson, J.M. Callow
Age determination of mallards 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...
Authors
Gary L. Krapu, Douglas H. Johnson, C.W. Dane
Modeling sandhill crane population dynamics Modeling sandhill crane population dynamics
The impact of sport hunting on the Central Flyway population of sandhill cranes (Grus canadensis) has been a subject of controversy for several years. A recent study (Buller 1979) presented new and important information on sandhill crane population dynamics. The present report is intended to incorporate that and other information into a mathematical model for the purpose of assessing the...
Authors
Douglas H. Johnson
Mathematics and mallard management 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...
Authors
L.M. Cowardin, Douglas H. Johnson
Forty-second breeding bird census - mixed prairie I-V and VIII Forty-second breeding bird census - mixed prairie I-V and VIII
Abstract has not been submitted
Authors
Douglas H. Johnson
Forty-second breeding bird census - Kentucky blue grass prairie Forty-second breeding bird census - Kentucky blue grass prairie
Abstract has not been submitted
Authors
Douglas H. Johnson