| Survival is the most critical vital rate for population viability in birds. However, survival is difficult to study and manage in many species, especially those that are threatened or endangered. We used mark-resight observations of uniquely banded snowy plovers (Charadrius nivosus nivosus), a population listed as threatened under the federal Endangered Species Act, to quantify seasonal and annual variation in survival. The return of individuals to non-breeding flocks was high (75-81%) between years. Apparent survival varied seasonally, with the lowest estimates (0.881 +/- 0.01) occurring during late winter (i.e., February-March) and highest during the breeding season (0.967 +/- 0.005). Annual apparent survival estimates were higher than previously reported for other populations along the Pacific Coast, with estimates similar to return rates. We discuss the conservation implications of our findings in the context of population viability and management of factors that may affect seasonal variation in survival.
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