SummaryObservations on eight pairs of Pied OystercatchersHaematopus ostralegus longirostrisat Mortimer Bay provide information on breeding success and adult survival. The species is long-lived but the low annual adult mortality is offset by low breeding success. Compared with other populations, the Australian race is characterised by a relatively small clutch size, a long incubation period, a long interval between hatching and flying and a very high age at first breeding. I suggest that breeding territories are at a premium, and that many sites are only marginal.