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- Distribution (2)
- North Dakota (2)
- Wilcoxon-Mann-Whitney test vs. t test. (1)
- Aerial survey (1)
- Ammodramus Leconteii (1)
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- Antilocapra americana (1)
- Blue grosbeak (1)
- Conservation Reserve Program (1)
- Guiraca caerulea (1)
- Hypothesis testing (1)
- Le Conte's Sparrow (1)
- Nonparametric methods (1)
- Normal distribution (1)
- Northern Great Plains (1)
- Parameter estimation (1)
- Population estimation (1)
- Pronghorn (1)
- Strip transect (1)
Articles 1 - 11 of 11
Full-Text Articles in Social and Behavioral Sciences
Contributions Of The Conservation Reserve Program To Populations Of Breeding Birds In North Dakota, Douglas Johnson, Lawrence Igl
Contributions Of The Conservation Reserve Program To Populations Of Breeding Birds In North Dakota, Douglas Johnson, Lawrence Igl
USGS Northern Prairie Wildlife Research Center
Previous studies have shown that habitat provided by the Conservation Reserve Program (CRP), a feature of the 1985 farm bill, is used by many birds. The present study quantitatively assesses the importance of the CRP by estimating changes in breeding bird populations of North Dakota projected if CRP land would revert to cultivation. Of 18 species that were common in CRP or crop fields or both, 12 were more abundant in CRP habitats. Six of these species had suffered significant population declines during 1967-1990, according to the North American Breeding Bird Survey. In contrast, none of the six species that …
Modified Transmitter Attachment Method For Adult Ducks, Pamela J. Pietz, David A. Brandt, Gary L. Krapu, Deborah A. Buhl
Modified Transmitter Attachment Method For Adult Ducks, Pamela J. Pietz, David A. Brandt, Gary L. Krapu, Deborah A. Buhl
USGS Northern Prairie Wildlife Research Center
The value of radio telemetry for waterfowl research depends on the availability of suitable methods of attaching transmitters. In previous studies, external transmitters attached to adult Mallards (Anas platyrhynchos) with sutures and glue did not stay on birds reliably. In an attempt to improve transmitter retention, a method of attachment was tested in which 4-g transmitters were attached mid-dorsally with sutures and with a stainless steel anchor-shaped wire inserted subcutaneously (anchor transmitters). Field tests indicated that all of 26 female Mallards and 63 of 65 female Gadwalls (Anas strepera) retained their anchor transmitters during 4369 bird-days …
Ecological Genetics For The 21st Century, Bonnie S. Bowen
Ecological Genetics For The 21st Century, Bonnie S. Bowen
USGS Northern Prairie Wildlife Research Center
In the spring of 1991, the University of North Carolina hosted a series of seminars on the topic of ecological genetics. Five distinguished researchers, Montgomery Slatkin, Sara Via, Michael Lynch, Janis Antonovics, and Joseph Travis, were each invited to present two talks: one a general overview of a research area in contemporary ecological genetics, and a second on a specific research topic. The ten chapters of Ecological Genetics are based on those presentations.
Neotropical Migrant Birds, Douglas H. Johnson
Neotropical Migrant Birds, Douglas H. Johnson
USGS Northern Prairie Wildlife Research Center
The latest vogue in bird conservation is concern over species that breed in the United States and Canada but winter mostly south of the United States-Mexico border. Many neotropical migrant birds have declined in number recently (although many have not). It is perhaps convenient to blame deforestation and other environmental abuses in the tropics for the declines in "our" birds, rather than to look inward at the abuses we in the United States have inflicted. Nonetheless, the concern about neotropical migrants, institutionalized by the Partners in Flight program, has served several purposes. For one, biologists are taking a broader view …
Using Known Populations Of Pronghorn To Evaluate Sampling Plans And Estimators, Kathy M. Kraft, Douglas H. Johnson, Jack M. Samuelson, Stephen H. Allen
Using Known Populations Of Pronghorn To Evaluate Sampling Plans And Estimators, Kathy M. Kraft, Douglas H. Johnson, Jack M. Samuelson, Stephen H. Allen
USGS Northern Prairie Wildlife Research Center
Although sampling plans and estimators of abundance have good theoretical properties, their performance in real situations is rarely assessed because true population sizes are unknown. We evaluated widely used sampling plans and estimators of population size on 3 known clustered distributions of pronghorn (Antilocapra americana). Our criteria were accuracy of the estimate, coverage of 95% confidence intervals, and cost. Sampling plans were combinations of sampling intensities (16, 33, and 50%), sample selection (simple random sampling without replacement, systematic sampling, and probability proportional to size sampling with replacement), and stratification. We paired sampling plans with suitable estimators (simple, ratio, …
Contributions Of The Conservation Reserve Program To Populations Of Breeding Birds In North Dakota, Douglas H. Johnson, Lawrence Igl
Contributions Of The Conservation Reserve Program To Populations Of Breeding Birds In North Dakota, Douglas H. Johnson, Lawrence Igl
USGS Northern Prairie Wildlife Research Center
Previous studies have shown that habitat provided by the Conservation Reserve Program (CRP), a feature of the 1985 farm bill, is used by many birds. The present study quantitatively assesses the importance of the CRP by estimating changes in breeding bird populations of North Dakota projected if CRP land would revert to cultivation. Of 18 species that were common in CRP or crop fields or both, 12 were more abundant in CRP habitats. Six of these species had suffered significant population declines during 1967-1990, according to the North American Breeding Bird Survey. In contrast, none of the six species that …
Effects Of Climate On Numbers Of Northern Prairie Wetlands, Diane Larson
Effects Of Climate On Numbers Of Northern Prairie Wetlands, Diane Larson
USGS Northern Prairie Wildlife Research Center
The amount of water held in individual wetland basins depends not only on local climate patterns but also on groundwater flow regime, soil permeability, and basin size. Most wetland basins in the northern prairies hold water in some years and are dry in others. To assess the potential effect of climate change on the number of wetland basins holding water in a given year, one must first determine how much of the variability in number of wet basins is accounted for by climatic variables. I used multiple linear regression to examine the relationship between climate variables and percentage of wet …
A Noteworthy Record And The Breeding Distribution Of The Blue Grosbeak In North Dakota, Lawrence D. Igl
A Noteworthy Record And The Breeding Distribution Of The Blue Grosbeak In North Dakota, Lawrence D. Igl
USGS Northern Prairie Wildlife Research Center
The northern limit of the blue grosbeak's (Guiraca caerulea) breeding distribution occurs in southern North Dakota. Records of the blue grosbeak in North Dakota are uncommon. Here, I report my observation of a blue grosbeak at a site where the species was recorded 25 years earlier. A summary of the species' distribution and records in North Dakota are provided.
Dramatic Increase Of Le Conte's Sparrow In Conservation Reserve Program Fields In The Northern Great Plains, Lawrence D. Igl, Douglas H. Johnson
Dramatic Increase Of Le Conte's Sparrow In Conservation Reserve Program Fields In The Northern Great Plains, Lawrence D. Igl, Douglas H. Johnson
USGS Northern Prairie Wildlife Research Center
During a continuing investigation in the northern Great Plains, we documented substantial increases of the Le Conte's Sparrow (Ammodramus Leconteii) in Conservation Reserve Program (CRP) fields in 1994 compared with 1990-93. The most dramatic increases occurred in Eddy County, North Dakota, and Sheridan County, Montana. The changes in habitat associated with the drought from 1989 to early 1993 and above-normal precipitation from mid-1993 through mid-1994 likely produced favorable breeding conditions for this species in CRP fields in 1994.
Statistical Sirens: The Allure Of Nonparametrics, Douglas H. Johnson
Statistical Sirens: The Allure Of Nonparametrics, Douglas H. Johnson
USGS Northern Prairie Wildlife Research Center
Although nonparametric statistical methods have a role to play in the analysis of data, often their virtues are overstated and their deficiencies overlooked. A recent Special Feature in Ecology advocated nonparametric methods because of an erroneously stated advantage that they require no assumptions regarding the distribution underlying the observations. The present paper points out some often-ignored features of nonparametric tests comparing two means, and advocates parameter estimation as a preferred alternative to hypothesis testing in many situations.
Factors Associated With Duck Nest Success In The Prairie Pothole Region Of Canada, Raymond J. Greenwood, Alan B. Sargeant, Douglas H. Johnson, Lewis M. Cowardin, Terry L. Shaffer
Factors Associated With Duck Nest Success In The Prairie Pothole Region Of Canada, Raymond J. Greenwood, Alan B. Sargeant, Douglas H. Johnson, Lewis M. Cowardin, Terry L. Shaffer
USGS Northern Prairie Wildlife Research Center
Populations of some dabbling ducks have declined sharply in recent decades and information is needed to understand reasons for this. During 1982-85, we studied duck nesting for 1-4 years in 17 1.6 by 16.0-km, high-density duck areas in the Prairie Pothole Region (PPR) of Canada, 9 in parkland and 8 in prairie. We estimated nest-initiation dates, habitat preferences, nest success, and nest fates for mallards (Anas platyrhynchos), gadwalls (A. strepera), blue-winged teals (A. discors), northern shovelers (A. clypeata), and northern pintails (A. acuta). We also examined the relation of mallard …