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Full-Text Articles in Social and Behavioral Sciences
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, …
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.