Apparent survival of Snowy Plovers (Charadrius nivosus) varies with reproductive effort and year and between sexes

Abstract

Abstract. Life history theory predicts a tradeoff between reproductive effort and survival, which suggests that some management practices aimed at increasing productivity may compromise population growth. We analyzed a 10-year data set of 225 individually marked Snowy Plovers (Charadrius nivosus), a threatened shorebird, to determine whether individual reproductive effort was correlated with low apparent survival. Most adults resided in the population an average of 2 years (range: 1–10 years), during which females laid 3–60 eggs, and both males and females invested considerable time in incubation and brooding. Apparent survival varied annually and was higher for males than for females. Contrary to theory, we found no evidence that increased reproductive effort, either current or cumulative, compromised survival. Instead, apparent survival was correlated positively with incubation time, which may be related to either high-quality individuals having high reproductive rates and high survival or permanent emi...