Table 6 Calculations of the survival of migrant Semipalmated Sandpipers at Paracas in each culmen length size class. For example, survival in the 17 mm culmen length size class is 0.710. These constitute 23% of the birds at Paracas. We estimate using the above procedure that 57% are migrants, so 43% oversummer. Oversummer survival is 0.81. Therefore, if overall survival of the size class is 0.710, migrant survival is 0.635, and oversummering gives a survival advantage of 18%

From: Oversummering juvenile and adult Semipalmated sandpipers in Perú gain enough survival to compensate for foregone breeding opportunity