Olfactory acuity in the common raven (Corvus corax).

The efficacy with which ravens can locate concealed carrion and similar foods has been noted from antiquity. This ability has been claimed in folklore to indicate an acute sense of smell. Contemporary opinion among ornithologists is that the sense of smell is weak at best in passerines, and particularly so in corvids which lack developed olfactory apparatus. Four studies were performed to test whether ravens could find hidden food (fresh ground fish) under conditions where scent was presumed to be the sole cue. The subjects, captive juvenile ravens (five males and three females) capably chose which one in a pair of containers held food buried under 2.0 cm of No. 4 gravel, discovered food concealed under as much as 2.5 cm of gravel, and located as little as 1.0 g of food covered by 1.5 cm of gravel. The several findings are consistent with the possibility that ravens can use olfactory cues to find food.