Western Snowy Plover Charadrius Alexandrinus Nivosus Chick Survival In Two Habitats In Humboldt County California PDF Download

Survival is an important vital rate that contributes to population viability, but is infrequently monitored and studied, especially compared to productivity. Furthermore, factors that limit survival and the relative effect on survival are often unknown. I used mark-resight observations of a small (~350) population of threatened Snowy Plovers (Charadrius nivosus nivosus) to quantify seasonal and annual variation in survival and movement between three coastal locations across ~70 km in Humboldt County, California. The return of individuals to non-breeding flocks at three locations was high between years (75-81%). Movement between three locations varied greatly, although most (n = 137) individuals resided at a single location throughout the 7-month study period (Sep-Mar). Apparent survival was lowest (0.88 ± 0.02) during late winter (Feb-Mar), and highest during the breeding season (0.97 ± 0.005). Annual survival was also higher in this study than previously reported for the population (0.85 ± 0.03). Given that apparent survival is predictably lowest during the winter (Dec-Mar), management directed at protecting non-breeding plover flocks from disturbance and other threats may make plovers less susceptible to mortality.