Master's Theses

Document Type

Thesis - campus only access

Date of Award

Spring 2009

Degree Name

Master of Science (MS)

Department

Biology

Advisor

Greg Farley

Abstract

Throughout much of its range, Snowy Plover (Charadrius alexandrines nivosus) numbers have been declining over the past two decades. In fact, the Pacific Coast population has been designated as “Threatened” under the Endangered Species Act. Inland populations also have experienced declines and have been given "Priority Status" by many bird conservation organizations and state wildlife agencies. The expansive mudflats and playas of the Great Salt Lake shoreline provide ideal breeding habitat for the Snowy Plover. In 2008, I investigated the breeding biology of Snowy Plover at three study sites at Great Salt Lake. Areas with a high probability of nesting sites were selected based on substrate type, vegetative growth, and proximity to water, in addition to bird abundance and activity. Nests were located by observing parental behavior, cues indicative of nesting and systematically searching nearby areas. I evaluated microhabitat characteristics associated with possible nest-site selection and density-dependent factors affecting nest success. The combined area of the three study sites totaled 1350 ha, and the mean number of nests per ha equaled 0.08. I located a total of 112 nests and was able to assess the fate of the majority (n=109; 97%) Sixty-five of the 109 nests were determined to have at least one young hatch successfully, resulting in an apparent nesting success of 60% (95% CI: 50 - 69%). Mayfield estimates were determined with 1,558 exposure days and resulted in 46% (95% CI: 37 - 58%) nesting success and 97% (95% CI: 96 - 98%) daily survival probability. A total of 44 nests failed during the 2008 breeding season. Predation was the cause of failure for 86% of the unsuccessful nests; 9% of the nests failed due to flooding; and 5% were due to an unknown cause. When all sites are combined, green vegetation cover at nests was significantly different between successful and preyed upon nests (F = 33.9, df= 101, t=3.41. P = 0.001); green vegetation around nests was 7% higher at successful nests compared to preyed upon nests. No other general relationships in nest surroundings were observed between successful and preyed upon nests. Data collected during the 2008 breeding season at Great Salt Lake will assist in further understanding the breeding biology of inland populations of Snowy Plover.

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Rights

© 2009 Christian N. Edwards

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