The lower extremity of the face below the mouth; the point of the under jaw.
The exterior or under surface embraced between the branches of the lower jaw bone, in birds.
The chin is the area just beneath the bill, above the throat. It is relatively small on most birds, but some put it to good use. Blue jays, for instance, have lots of feathers at the base of their beak and on their chin as well. These feathers come in handy many a time when searching for the perfect seed in a pile and thrashing the bad ones away. I've been annoyed many times when blue jays do this, shoveling huge groups of sunflower seeds off onto the ground to find the right one somewhere deep in the pile. Of course, the chin isn't completely useless for identification either, to get back on the subject. Ravens are discernable from crows virtually only by their slightly larger size and shaggy throat / chin feathers.
ventral leathering below the bill ending where throat begins. Back to identifying diagram
The front part of the face below the lips, overlying the mandible or jaw bone.
anterior ventral portion of the lower jaw
the protruding part of the lower jaw
Medically, the mentum. The lower portion of the face below the lower lip including the prominence of the lower jaw and the line of fusion of the two separate halves of the jawbone ( mandible ). This line of fusion (called the symphysis menti) encloses a triangular area at tip of the chin (termed the mental protuberance). On each side, below the second premolar tooth, is the mental foramen , an opening for the passage of blood vessels and a nerve that supply the chin. See the entire definition of Chin
The chin is the general area of the face just below the bill. The bird's chin does not protrude like a human's chin and therefore is less prominent.
Part of the face below the bill.