AN ESTIMATE OF LIFETIME REPRODUCTIVE SUCCESS FOR THE COMMON SANDPIPERACTITIS-HYPOLEUCOS

Field evidence, interpreted conservatively, suggests that female Commo n Sandpipers reared only 1.46 fledglings in their lifetimes. Fledgling output was positively correlated with longevity, and improved over th e first 3 years. Over half the fledglings were produced by just 14% of the females. Calculating the likely errors in our interpretation of t he field data suggests that the true production might have been 3.46 f ledglings per female lifetime, giving just enough recruits to balance the normal adult mortality. Because recruits rarely return to breed in their natal sites, we cannot estimate recruitment or survival over th e first winter directly, and this is a major difficulty in our underst anding of this species.