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
Genetic variations in the midcontinental population of sandhill crane, Grus canadenis
Three subspecies of sandhill crane (Grus canadensis) are recognized in the Midcontinental population, the lesser (Grus c. canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). Blood samples collected on the population's primary spring staging area in Nebraska, U.S.A., were used to resolve the genetic relationship among these subspecies. Phylogenetic analysis of 27 G. canadensis, by DNA
Authors
Jessica L. Petersen, Richard Bischof, Gary Krapu, Allen L. Szalanski
Factors affecting gadwall brood and duckling survival in prairie pothole landscapes
Waterfowl biologists need reliable predictors of brood and duckling survival to accurately estimate recruitment rates. We examined 30-day survival rates of gadwall (Anas strepera) broods (1992-1994) and ducklings (1990-1994) in eastern North Dakota, USA, during years when water conditions ranged from extremely dry to extremely wet. We evaluated effects of several variables on brood survival: (1) p
Authors
P.J. Pietz, G.L. Krapu, D.A. Brandt, R. R. Cox
Genetic variation in the midcontinental population of sandhill cranes, Grus canadensis
Three subspecies of sandhill crane (Grus canadensis) are recognized in the Midcontinental population, the lesser (Grus c. canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). Blood samples collected on the population's primary spring staging area in Nebraska, U.S.A., were used to resolve the genetic relationship among these subspecies. Phylogenetic analysis of 27 G. canadensis, by DNA
Authors
Jessica L. Petersen, R. Bischof, G.L. Krapu, A.L. Szalanski
Does increasing daylength control seasonal changes in clutch sizes of Northern Pintails (Anas acuta)?
We evaluated spatiotemporal variation in clutch sizes of Northern Pintails (pintails; Anas acuta) nesting in California (1985 to 1996), North Dakota (1982 to 1985), Saskatchewan (1982 to 1985) and Alaska (1991 to 1993) to determine whether seasonal declines in clutch size varied in ways that were consistent with a controlling influence of increasing day length. Pintails began nesting in mid-March
Authors
G.L. Krapu, G.A. Sargeant, A.E.H. Perkins
Recommendations for the attachment of satellite transmitters to cranes
Recent advances in miniaturization of satellite transmitters have resulted in thumb-sized packages weighing less than 30 g. These are smaller than VHF radios routinely mounted on crane leg bands. With this development and with favorable signal reception results, there is no need for, and much to recommend against the continued use of back-pack mounts. We provide details for leg-mount attachment
Authors
D. H. Ellis, P.W. Howey, G.L. Krapu
Factors associated with Autumn rearing of duck broods in temperate North America
Dabbling ducks Genus Anas occasionally nest during mid- and late summer in the Prairie Pothole Region (PPR) of midcontinent North America but little information is available on their Autumn-reared broods or those of other duck genera. Densities, species composition, and wetland habitat use by Autumn reared duck broods (age classes I and II) were determined on randomly distributed transects on a 3,
Authors
G.L. Krapu, D.A. Brandt, J.A. Beiser
Decline in waste corn affecting spring staging habits of sandhill cranes in the central Platte River Valley, Nebraska
No abstract available.
Authors
G.L. Krapu, D.A. Brandt
Mallard brood survival in prairie pothole landscapes
No abstract available.
Authors
G.L. Krapu, P.J. Pietz, D.A. Brandt, R. R. Cox
Effects of water conditions on clutch size, egg volume, and hatchling mass of mallards and gadwalls in the Prairie Pothole Region
We examined the relationship between local water conditions (measured as the percent of total area of basins that was covered by water) and clutch size, egg volume, and hatchling mass of Mallards (Anas platyrhynchos) and Gadwalls (A. strepera) on four study sites in the Prairie Pothole Region of North Dakota and Minnesota, 1988-1994. We also examined the relationship between pond density and clutc
Authors
Pamela J. Pietz, Gary L. Krapu, Deborah A. Buhl, David A. Brandt
Factors limiting mallard brood survival in prairie pothole landscapes
In order to estimate mallard (Anas platyrhynchos) production from managed and unmanaged lands, waterfowl biologists need measurable predictors of brood survival. We evaluated effects of percent of seasonal basins holding water (WETSEAS), percent of upland landscape in perennial cover (PERNCOVER), rainfall (RAIN), daily minimum ambient temperature (TMIN), hatch date (HATCHDATE), brood age (BA; 0-7
Authors
Gary L. Krapu, Pamela J. Pietz, David A. Brandt, Robert R. Cox
Effects of water conditions on clutch size, egg volume, and hatchling mass of mallards and gadwalls in the Prairie Pothole Region
We examined the relationship between local water conditions (measured as the percent of total area of basins covered by water) and clutch size, egg volume, and hatchling mass of Mallards (Anas platyrhynchos) and Gadwalls (A. strepera) on four study sites in the Prairie Pothole Region of North Dakota and Minnesota, 1988–1994. We also examined the relationship between pond density and clutch size of
Authors
P.J. Pietz, G.L. Krapu, D. A. Buhl, D.A. Brandt
Temporal flexibility of reproduction in temperate-breeding dabbling ducks
I compared nesting intervals during three consecutive years in five species of temperate-nesting dabbling ducks (Mallard [Anas platyrhynchos], Northern Pintail [Anas acuta], Northern Shoveler [Anas clypeata], Blue-winged Teal [Anas discors], Gadwall [Anas strepera]) and assessed whether differences existed in timing of refractoriness. Most nesting by females of all five species ended by the summer
Authors
Gary L. Krapu
Science and Products
Filter Total Items: 105
Genetic variations in the midcontinental population of sandhill crane, Grus canadenis
Three subspecies of sandhill crane (Grus canadensis) are recognized in the Midcontinental population, the lesser (Grus c. canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). Blood samples collected on the population's primary spring staging area in Nebraska, U.S.A., were used to resolve the genetic relationship among these subspecies. Phylogenetic analysis of 27 G. canadensis, by DNA
Authors
Jessica L. Petersen, Richard Bischof, Gary Krapu, Allen L. Szalanski
Factors affecting gadwall brood and duckling survival in prairie pothole landscapes
Waterfowl biologists need reliable predictors of brood and duckling survival to accurately estimate recruitment rates. We examined 30-day survival rates of gadwall (Anas strepera) broods (1992-1994) and ducklings (1990-1994) in eastern North Dakota, USA, during years when water conditions ranged from extremely dry to extremely wet. We evaluated effects of several variables on brood survival: (1) p
Authors
P.J. Pietz, G.L. Krapu, D.A. Brandt, R. R. Cox
Genetic variation in the midcontinental population of sandhill cranes, Grus canadensis
Three subspecies of sandhill crane (Grus canadensis) are recognized in the Midcontinental population, the lesser (Grus c. canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). Blood samples collected on the population's primary spring staging area in Nebraska, U.S.A., were used to resolve the genetic relationship among these subspecies. Phylogenetic analysis of 27 G. canadensis, by DNA
Authors
Jessica L. Petersen, R. Bischof, G.L. Krapu, A.L. Szalanski
Does increasing daylength control seasonal changes in clutch sizes of Northern Pintails (Anas acuta)?
We evaluated spatiotemporal variation in clutch sizes of Northern Pintails (pintails; Anas acuta) nesting in California (1985 to 1996), North Dakota (1982 to 1985), Saskatchewan (1982 to 1985) and Alaska (1991 to 1993) to determine whether seasonal declines in clutch size varied in ways that were consistent with a controlling influence of increasing day length. Pintails began nesting in mid-March
Authors
G.L. Krapu, G.A. Sargeant, A.E.H. Perkins
Recommendations for the attachment of satellite transmitters to cranes
Recent advances in miniaturization of satellite transmitters have resulted in thumb-sized packages weighing less than 30 g. These are smaller than VHF radios routinely mounted on crane leg bands. With this development and with favorable signal reception results, there is no need for, and much to recommend against the continued use of back-pack mounts. We provide details for leg-mount attachment
Authors
D. H. Ellis, P.W. Howey, G.L. Krapu
Factors associated with Autumn rearing of duck broods in temperate North America
Dabbling ducks Genus Anas occasionally nest during mid- and late summer in the Prairie Pothole Region (PPR) of midcontinent North America but little information is available on their Autumn-reared broods or those of other duck genera. Densities, species composition, and wetland habitat use by Autumn reared duck broods (age classes I and II) were determined on randomly distributed transects on a 3,
Authors
G.L. Krapu, D.A. Brandt, J.A. Beiser
Decline in waste corn affecting spring staging habits of sandhill cranes in the central Platte River Valley, Nebraska
No abstract available.
Authors
G.L. Krapu, D.A. Brandt
Mallard brood survival in prairie pothole landscapes
No abstract available.
Authors
G.L. Krapu, P.J. Pietz, D.A. Brandt, R. R. Cox
Effects of water conditions on clutch size, egg volume, and hatchling mass of mallards and gadwalls in the Prairie Pothole Region
We examined the relationship between local water conditions (measured as the percent of total area of basins that was covered by water) and clutch size, egg volume, and hatchling mass of Mallards (Anas platyrhynchos) and Gadwalls (A. strepera) on four study sites in the Prairie Pothole Region of North Dakota and Minnesota, 1988-1994. We also examined the relationship between pond density and clutc
Authors
Pamela J. Pietz, Gary L. Krapu, Deborah A. Buhl, David A. Brandt
Factors limiting mallard brood survival in prairie pothole landscapes
In order to estimate mallard (Anas platyrhynchos) production from managed and unmanaged lands, waterfowl biologists need measurable predictors of brood survival. We evaluated effects of percent of seasonal basins holding water (WETSEAS), percent of upland landscape in perennial cover (PERNCOVER), rainfall (RAIN), daily minimum ambient temperature (TMIN), hatch date (HATCHDATE), brood age (BA; 0-7
Authors
Gary L. Krapu, Pamela J. Pietz, David A. Brandt, Robert R. Cox
Effects of water conditions on clutch size, egg volume, and hatchling mass of mallards and gadwalls in the Prairie Pothole Region
We examined the relationship between local water conditions (measured as the percent of total area of basins covered by water) and clutch size, egg volume, and hatchling mass of Mallards (Anas platyrhynchos) and Gadwalls (A. strepera) on four study sites in the Prairie Pothole Region of North Dakota and Minnesota, 1988–1994. We also examined the relationship between pond density and clutch size of
Authors
P.J. Pietz, G.L. Krapu, D. A. Buhl, D.A. Brandt
Temporal flexibility of reproduction in temperate-breeding dabbling ducks
I compared nesting intervals during three consecutive years in five species of temperate-nesting dabbling ducks (Mallard [Anas platyrhynchos], Northern Pintail [Anas acuta], Northern Shoveler [Anas clypeata], Blue-winged Teal [Anas discors], Gadwall [Anas strepera]) and assessed whether differences existed in timing of refractoriness. Most nesting by females of all five species ended by the summer
Authors
Gary L. Krapu