Factors influencing nest survival and renesting by Piping Plovers in the Great Lakes region

Renesting is an important breeding strategy used by birds to compensate for nest failure. If birds renest, clutch removal for captive rearing can be used to augment endangered populations; however, not all individuals renest following nest loss, and later nesting attempts may have lower survival rates and clutch sizes. We investigated variation in nest initiation date, clutch size, daily nest survival, renesting propensity, and renesting intervals of federally endangered Great Lakes Piping Plovers (Charadrius melodus) from 1993 to 2010. We also compared productivity under hypothetical clutch removal for captive rearing vs. non-removal scenarios. Nest initiation date was earlier for older adults and was more strongly affected by female than male age. Clutch size and nest survival decreased with later nest initiation, and nest survival increased with male age and nest age until close to hatching. Overall, Piping Plovers replaced 49% of failed nests. Renesting propensity decreased with later date, increased with each successive nesting attempt, and varied according to cause of failure; probability of renesting was highest following flooding and lowest for inviable clutches. Renesting intervals increased with age of the previous nest and averaged 4.2 days longer for birds that changed mates. Results also indicated that, compared to leaving eggs in situ, clutch removal for captive rearing would produce 43% fewer 1-year-old recruits, partly because renesting does not fully offset clutch removal; therefore, efforts to increase fledging success in this endangered population should focus on proactively protecting nests in situ rather than relying on collection of eggs for captive rearing.