Factors Influencing Snowy Plover Nest Survival on Ocean-Fronting Beaches in Coastal Northern California

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

“…Our nest survival estimates were similar to interior populations of Snowy Plover in the Southern High Plains of Texas (0.07 -0.33; Saalfeld et al 2011), Kansas (0.11 -0.29;Sexson and Farley 2012) and Oklahoma (0.37 -0.58;Winton et al 2000). Coastal populations of Snowy Plover have experienced variable nest survival depending on the region, including low rates of success in northern California (0.05 -0.08; Hardy and Colwell 2012) and Oregon (0.13; Wilson-Jacobs and Meslow 1984). Our estimates have a lower limit than estimates from southern California (0.36 -0.77; Powell et al 2002), and were lower than those reported in Puerto Rico (0.61 -0.73; Lee 1989).…”

Lifetime reproductive success of Snowy Plovers in coastal northern California

“…Since 2004, researchers also conducted 500 m point counts at 20 minute intervals to assess the threat of predation and human activity at plover breeding sites (Colwell et al 2010a, Burrell and Colwell 2012, Hardy and Colwell 2012. removed individuals from the initial dataset that were not uniquely marked (n males =17, n females =8), those with documented breeding records outside of Humboldt County (n males =15, n females =26), those that bred in Humboldt County before 2001 when data collection was less reliable (n males =18, n females =22), and those that had an equal number of nesting attempts on sand and gravel substrates (n males =3, n females =4).…”

“…It is important to note that Hardy and Colwell (2012) found little evidence of a relationship between substrate and nest survival for plovers breeding on beaches in Humboldt county. There was a positive relationship between nest survival and debris heterogeneity, but this relationship was weak.…”

“…There was a positive relationship between nest survival and debris heterogeneity, but this relationship was weak. The authors speculated that landscape scale differences in predator abundance may have overwhelmed the effects of habitat characteristics at the nest site (Hardy and Colwell 2012).…”

“…A stronger relationship between LRS and human activity may have resulted if this study took place in central or southern California, where human activity at plover breeding sites is higher (Powell et al 2002, Ruhlen et al 2003, Lafferty et al 2006). The weak relationship between human activity and LRS might also be explained by the fact that, due to high rates of nest and chick depredation in RU2, eggs and chicks may have little contact with humans (Burrell 2010, Hardy and Colwell 2012, Colwell et al 2013. Lastly, this relationship may have been weak due to the scale and methods that I used to summarize human activity for each plover.…”