killdeer, common North American shorebird related to the plover and the sandpiper. It is about 10 in. (25 cm) in length and its plumage is grayish brown with a double black band across a white breast. Its simple nest is a depression in the soil or gravel. The killdeer is classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Charadriiformes, family Charadriidae.