Publications

Avian botulism is an important disease affecting many species of waterbirds in North America, but the environmental conditions that initiate outbreaks are poorly understood. To determine wetland attributes associated with outbreaks of avian botulism in waterbirds at the Sacramento National Wildlife Refuge (SNWR), California, we compared environmental characteristics between wetlands...

Mallards (Anas platyrhynchos) frequently pair during winter, and duck hunting seasons have been extended until the end of January in several southern states in the Mississippi Flyway. Therefore, we simulated dissolution of pair bonds from natural or hunting mortality by removing mates of wild-strain, captive, yearling female mallards in late January 1996 and early February 1997 to test...

The climate of the North American Great Plains is highly dynamic, with great year-to-year variability in precipitation and periodic, often extreme, wet and dry cycles (Bragg 1995). Drought is a major force of ecological disturbance on the Great Plains and has played a key role in directing the evolution of the grassland biota of this region (Knopf and Samson 1997). Although grassland...

Abstract has not been submitted

The Conservation Reserve Program, initiated in 1985, was designed primarily to reduce soil erosion and crop surpluses. A secondary benefit was the provision of habitat for wildlife. Grassland bird populations, many of which declined in the decades prior to the Conservation Reserve Program, may have benefited from the Conservation Reserve Program if reproduction in this newly available...

Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 5,500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds frequently are observed outside the breeding range indicated...

The North American breeding population of northern pintails (Anas acuta) has reached previously unprecedented low numbers 4 times since 1983. Because pintails show high fidelity to wintering areas, regional survival estimates and identification of factors influencing survival are needed to guide management of wintering pintails. We used radiotelemetry to estimate survival rates of female...

The North American breeding population of northern pintails (Anas acuta) has reached previously unprecedented low numbers 4 times since 1983. Because pintails show high fidelity to wintering areas, regional survival estimates and identification of factors influencing survival are needed to guide management of wintering pintails. We used radiotelemetry to estimate survival rates of female...

No abstract available.

The role of riparian vegetation is assessed quantitatively by using a five-decade record of valley bottom vegetation and channel dynamics developed from historical aerial photography. A 12-kilometer reach of a typical Ozarks stream was mapped using aerial photographs from 1938, 1948, 1955, 1965, 1976, and 1989; maps were then analyzed in a digital geographic information system. Analysis...

Identification and assessment of the relative importance of factors affecting duckling growth and survival are essential for effective management of mallards on breeding areas. For each of 3 years (1993-95), we placed F1-generation wild mallard (Anas platyrhynchos) females on experimental wetlands and allowed them to mate, nest, and rear broods for 17 days. We manipulated invertebrate...

Checklist and “Pollard Walk” butterfly survey methods were contemporaneously applied to seven public sites in North Dakota during the summer of 1995. Results were compared for effect of method and site on total number of butterflies and total number of species detected per hour. Checklist searching produced significantly more butterfly detections per hour than Pollard Walks at all sites...