They are medium to large birds with strong black or yellow black bills, large yellow eyes—which give them a reptilian appearance—and cryptic plumage. The names thick-knee and stone-curlew are both in common use, the preference among authorities for one term or the other varying from year to year. The term stone-curlew owes its origin to the broad similarities with true curlews (which are not closely related). Thick-knee refers to the prominent joints in the long yellow or greenish legs and apparently originated with a name coined in 1776 for B. oedicnemus, the Eurasian stone-curlew. Obviously the heel (ankle) and the knee are confused here.