Ghost crab preys on a Piping Plover chick

摘要

East Coast Piping Plovers (Charadrius melodus) were listed as threatened because of declining populations (Fed. Register 1985) due to loss of habitat and human disturbance. Predation of nests and young has been cited as one cause of the decline (Fed. Register 1985, Dyer et al. 1988, Melvin et al. 1991, Haig 1992). Here we describe predation of a Piping Plover chick by a ghost crab (Ocypode quadrata) on Assateague Island National Seashore, Maryland. On 7 July 1988, 08:45 EDT, JPL and LLL approached a brood of two 8-day-old Piping Plover chicks and two adults to complete behavioral observations (Loegering 1992). From > 70 m, we observed the birds moving along the beach. Both chicks appeared healthy. One adult alarm-called when we initially approached; however, after we sat and remained motionless ( <2 min.) it appeared undisturbed. As the brood moved along the beach, the adults suddenly became alarmed and ran down the beach. We observed the brood for 13-15 min. but only saw one chick. We then walked toward our vehicle on the ocean tidal zone. As we crossed the path previously taken by the brood, we discovered a freshly killed plover chick 0.1 m from a ghost crab burrow. The chick had a laceration from the sternum to the pelvis, and much of the viscera was displaced or missing. The blood present was very wet and bright red. It weighed 9 g (partially eviscerated). We retreated 25 m and a ghost crab emerged from its burrow after approximately 3 min. We photographed the crab feeding on the chick. We dug the ghost crab out of its burrow, measured it, and released it unharmed (weight = 42.5 g, dorsal carapace width = 41 mm, dorsal carapace length = 32 mm).