Jodice, P.G.R., J. Thibault, S.A.Collins, M. Spinks, F.J. Sanders. 2014. Reproductive ecology of American Oystercatchers nesting on shell rakes. Condor 116:588-598.
Degradation of nesting habitat for coastal birds has led to the use of nontraditional nesting habitat. The American Oystercatcher is listed as a “Species of High Concern” by the U.S. Shorebird Conservation Plan and is declining in the southern portion of its US breeding range where ~50% of breeding oystercatchers nest on shell substrate instead of beachfront habitat. We measured daily survival rates during incubation and chick-rearing in shell rake habitats over five breeding seasons in the Cape Romain Region of South Carolina, USA. Of 354 nesting attempts monitored, 16.1% hatched at least one egg. The daily survival rate and probability of a nest succeeding during the incubation stage was 0.938 and 22.8%, respectively. Overwash and predation were the primary causes of nest loss. Of the 40 successful nests we monitored, 70.1% fledged at least one young. The daily survival rate of broods and probability of a brood succeeding for oystercatchers was 0.991 and 74.0%, respectively. Productivity in the Cape Romain Region is primarily being lost during the incubation phase when nests are exposed to overwash and predation. Mobile chicks may, however, be able to avoid flood events or predators by relocating to higher or more protected portions of a shell rake. It does not appear that the shell rakes being used for breeding in the Cape Romain Region are inferior compared to other habitats being used in other states. Our data suggest that conservation actions that target nest and chick loss from flooding and predation have the greatest opportunity to enhance reproductive success on these shell rakes, and that an assessment of the availability, structure, use, and protection status of shell rakes is warranted.