Gary Krapu, PhD
Dr. Gary Krapu is a Wildlife Biologist (Emeritus) at the USGS Northern Prairie Wildlife Research Center in Jamestown, North Dakota.
Science and Products
Filter Total Items: 105
Feeding ecology of pintail hens during reproduction
Food supply has been acknowledged as one of eight major external factors regulating the sexual cycles of birds (Marshall 1961). Several hypotheses have been advanced to explain the role of food supply as an ultimate factor regulating breeding (Marshall 1951; Lack 1954, 1968; Wynne-Edwards 1962; and others). Another potential influence of food is its being a proximate stimulus to breeding. When cer
Authors
G.L. Krapu
Foods of breeding pintails in North Dakota
Food habits of breeding pintails (Anas acuta) were studied relative to sex, land use, and reproductive condition during the spring and summer of 1969, 1970, and 1971 in eastern North Dakota. Hens and drakes, respectively, consumed 79.2 percent and 30.0 percent animal matter on nontilled wetlands and consumed 16.6 percent and 1.1 percent animal matter on tilled wetlands. Aquatic dipterans (primaril
Authors
G.L. Krapu
A biological survey of Kraft Slough
Abstract has not been submitted
Authors
G.L. Krapu, H. F. Duebbert
The prairie: to know it is to appreciate it
Abstract has not been submitted
Authors
J. T. Lokemoen, G.L. Krapu
Red-winged blackbirds nesting near Great Slave Lake, N.W.T
No abstract available.
Authors
Gary Krapu
Thirty-seventh breeding bird census - mixed prairie
Abstract has not been submitted
Authors
D. H. Johnson, G.L. Krapu
Mercury residues in pintails breeding in North Dakota
Livers of 42 pintail hens (Anas acuta) breeding in eastern North Dakota during the spring and early summer of 1969 and 1970 were analyzed for total mercury by the neutron activation technique. Mercury content on a wet weight basis ranged from 0.055 ppm to 9.512 ppm and averaged 0.888 ± 1.796 ppm (SD). Liver mercury levels of hens collected in early spring (prior to planting of crops) were signific
Authors
G.L. Krapu, G.A. Swanson, H.K. Nelson
A recent record of the meadow jumping mouse, Zapus hudsonius, in subarctic Canada
The occurrence of Zapus hudsonius is confirmed for the area lying N of the Mackenzie River and Great Slave Lake.
Authors
Gary Krapu, David L. Traugher
Waterfowl in relation to land use and water levels on the Spring Run Area
Low water levels during critical phases of the breeding cycle appear to have caused population declines of waterfowl and other marsh birds on the Spring Run Game Management Area. Pair-counts indicated a decline from 70 pairs of waterfowl in 1965 to 2 pairs in 1968. Nest success of upland nesting blue-winged teal (Anas discors) averaged 33% and mallards (Anas platyrhyncos) averaged 23%. Blue-winged
Authors
G.L. Krapu, D.R. Parsons, M.W. Weller
Science and Products
Filter Total Items: 105
Feeding ecology of pintail hens during reproduction
Food supply has been acknowledged as one of eight major external factors regulating the sexual cycles of birds (Marshall 1961). Several hypotheses have been advanced to explain the role of food supply as an ultimate factor regulating breeding (Marshall 1951; Lack 1954, 1968; Wynne-Edwards 1962; and others). Another potential influence of food is its being a proximate stimulus to breeding. When cer
Authors
G.L. Krapu
Foods of breeding pintails in North Dakota
Food habits of breeding pintails (Anas acuta) were studied relative to sex, land use, and reproductive condition during the spring and summer of 1969, 1970, and 1971 in eastern North Dakota. Hens and drakes, respectively, consumed 79.2 percent and 30.0 percent animal matter on nontilled wetlands and consumed 16.6 percent and 1.1 percent animal matter on tilled wetlands. Aquatic dipterans (primaril
Authors
G.L. Krapu
A biological survey of Kraft Slough
Abstract has not been submitted
Authors
G.L. Krapu, H. F. Duebbert
The prairie: to know it is to appreciate it
Abstract has not been submitted
Authors
J. T. Lokemoen, G.L. Krapu
Red-winged blackbirds nesting near Great Slave Lake, N.W.T
No abstract available.
Authors
Gary Krapu
Thirty-seventh breeding bird census - mixed prairie
Abstract has not been submitted
Authors
D. H. Johnson, G.L. Krapu
Mercury residues in pintails breeding in North Dakota
Livers of 42 pintail hens (Anas acuta) breeding in eastern North Dakota during the spring and early summer of 1969 and 1970 were analyzed for total mercury by the neutron activation technique. Mercury content on a wet weight basis ranged from 0.055 ppm to 9.512 ppm and averaged 0.888 ± 1.796 ppm (SD). Liver mercury levels of hens collected in early spring (prior to planting of crops) were signific
Authors
G.L. Krapu, G.A. Swanson, H.K. Nelson
A recent record of the meadow jumping mouse, Zapus hudsonius, in subarctic Canada
The occurrence of Zapus hudsonius is confirmed for the area lying N of the Mackenzie River and Great Slave Lake.
Authors
Gary Krapu, David L. Traugher
Waterfowl in relation to land use and water levels on the Spring Run Area
Low water levels during critical phases of the breeding cycle appear to have caused population declines of waterfowl and other marsh birds on the Spring Run Game Management Area. Pair-counts indicated a decline from 70 pairs of waterfowl in 1965 to 2 pairs in 1968. Nest success of upland nesting blue-winged teal (Anas discors) averaged 33% and mallards (Anas platyrhyncos) averaged 23%. Blue-winged
Authors
G.L. Krapu, D.R. Parsons, M.W. Weller