Factors Influencing Snowy Plover (Charadrius nivosus) Nest Survival at Great Salt Lake, Utah

Abstract

Reduced nest survival has been suggested as a primary cause for the decline of Snowy Plover (Charadrius nivosus) populations. The fates of Snowy Plover nests (n = 589) were determined from five locations at the Great Salt Lake in Utah during the 2003, 2005–2010 and 2012 breeding seasons. A five-stage hierarchical modeling procedure was used, and five competing models (ΔAICc < 2) that best described variation in nest survival were identified. These competing models included the influences of study site and year with a quadratic time trend and covariates quantifying nest age, temperature, precipitation, distance to water control structures (dikes), and nesting substrate (barren mudflat, vegetation patches, or conspicuous objects). Among unsuccessful nests (45.6%; n = 277), the most common cause of failure was predation (72.9%), followed by weather and abandonment (10.5% and 10.1%, respectively). Daily nest survival rates ranged from 0.89 to 0.97 and varied annually and across sites. Nests located on barren flats had lower daily nest survival than those located in vegetated patches or near conspicuous objects. Proximity to dikes influenced nest survival as nests within 100 m had lower daily survival rates than nests further than 100 m from dikes. The population of Snowy Plovers on the Great Salt Lake contributes substantially to an overall imperiled North American population. Managers should consider measures to reduce the attractiveness of dikes as nesting habitat to increase nest survival rates for Snowy Plover.