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

Abstract

Selection of a nest site that affords camouflage of eggs or incubating adults is thought to be strongly influenced by predation, especially for ground-nesting birds. Data from 115 Snowy Plover (Charadrius nivosus) nests were used to model relationships between nest survival, habitat characteristics, predator activity and human activity on four sandy, ocean-fronting beaches in coastal northern California from 2007–2009. Plover daily nest survival was higher at two southern sites (South Spit range = 0.98–0.99; Eel River Wildlife Area range = 0.91–0.96) compared with two northern sites (Mad River Beach range = 0.77–0.88; Clam Beach range = 0.79–0.89) where predator activity was appreciably higher. Nest survival was positively related to debris heterogeneity and negatively related to the amount of debris near the nest, but these relationships were weaker than the site-level effect. Although plovers select nest sites among cryptic debris in sparsely vegetated areas, restoration that creates and enhances such habitats may have limited utility at sites where predators are abundant. Thus, managers must carefully consider predator activity at the landscape level in order to maximize the effectiveness of fine-scale restoration efforts.