Incidental kill of dunlin and killdeer by strychnine.

Strychnine poisoning of 36 dunlin (Calidris alpina) and two killdeer (Charadrius vociferus) in Yolo County, California (USA) was documented from 11 to 17 December 1990. Birds were found dead on a field containing treated wheat seeds (337 micrograms strychnine/g seed) in postures consistent with the known physiopathology of strychnine poisoning: rapid rigor mortis, wings folded over backs, straightened toes, and fecal material extruding from vents. Five dunlin and two killdeer were necropsied, and their crop and stomach contents were analyzed by high performance liquid chromatography for the presence of strychnine. The mean (+/- SD) actual unabsorbed strychnine concentration per amount stomach content for the five dunlin was 110 (+/- 108) micrograms/g and for the two killdeer, 210 (+/- 109) micrograms/g. Shorebirds have not been identified previously as victims of pesticides.