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Full-Text Articles in Social and Behavioral Sciences
Spring-Migration Ecology Of Northern Pintails In South-Central Nebraska, Aaron T. Pearse, Gary L. Krapu, Robert R. Cox Jr., Bruce E. Davis
Spring-Migration Ecology Of Northern Pintails In South-Central Nebraska, Aaron T. Pearse, Gary L. Krapu, Robert R. Cox Jr., Bruce E. Davis
USGS Northern Prairie Wildlife Research Center
Spring-migration ecology of staging Northern Pintails, Anas acuta, was investigated in south-central Nebraska, USA. Habitat associations, local movements, settling patterns, arrival dates, residency times and survival were estimated from 71 radiomarked pintails during spring 2001, 2003 and 2004, and diet determined from 130 females collected during spring 1998 and 1999. Seventy-two percent of pintail diurnal locations were in palustrine wetlands, 7% in riverine wetlands, 3% in lacustrine wetlands, 6% in municipal sewage lagoons and irrigation reuse pits and 10.5% in croplands. Emergent wetlands with hemi-marsh conditions were used diurnally more often than wetlands with either open or closed vegetation …
A Historical Perspective: Changes In Grassland Breeding Bird Densities Within Major Habitats In North Dakota Between 1967 And 1992-1993, Lawrence D. Igl, Douglas H. Johnson, Harold A. Kantrud
A Historical Perspective: Changes In Grassland Breeding Bird Densities Within Major Habitats In North Dakota Between 1967 And 1992-1993, Lawrence D. Igl, Douglas H. Johnson, Harold A. Kantrud
USGS Northern Prairie Wildlife Research Center
Population declines of many grassland-nesting birds are now widely recognized. Fundamental to understanding these declines is knowing if they are caused by changes in the availability of suitable habitats or changes in the densities of birds within those habitats. We address that issue with information from systematic surveys of breeding birds throughout North Dakota in 1967, 1992, and 1993. We compared the availability of 8 major habitat types, and the densities of 24 species of grassland birds in each habitat type, for 128 randomly selected quarter-sections (64.7 ha or 160 ac) that were surveyed in each of those years. Between …