In birds, four main types of cutaneous mechanoreptors can be distinguished: Herbst corpuscles, Grandry corpuscles, Merkel cell receptors and Ruffini endings.
Avian Ruffini endings are stretch receptors that have been identified in the beaks of geese and the Japanese quail only. Encapsuled Ruffini endings (Ruffini corpuscles) are present in joint capsules. Merkel cells and Merkel cell corpuscules are present in the dermis of the beak and legs. Aquatic birds lack Merkel cells but have Grandry corpuscles instead.
Herbst and Grandry corpuscles are described in the galleries below.