(noun) The base of a bird's bill where the mandible and maxilla join. The area where the bills join may also be called the gape flange, while the entire interior of the mouth may be considered the gape. In young birds, the gape is often brightly colored to attract parent birds' attention in order to encourage more feeding – pink, red, yellow and orange are the most common gape colors. Some birds also have spots or markings inside the gape, such as the spotted gape of the zebra finch or the different stripes or bars in the gapes of different mannikin species.
Both bright colors and markings help make the gape more visible in low light conditions, such as inside a bird house or when a nest is in shadows.
The gape flange can remain fleshy and more brightly colored in many juvenile birds, which is useful after fledglings may leave the nest but are still dependent on their parents for additional care. Gradually the gape flange will shrink and turn dull and unnoticeable as birds age. In a few adult bird species, however, the gape can remain distinct and serves as a useful field mark, such as the pink gape of the bananaquit.
(verb) To open the mouth wide as in a begging, demanding behavior. This shows off the colors of the interior of the mouth to better advantage and attracts attention. Very young birds may gape when there is any stimulus in their immediate vicinity, such as motion on the nest that may indicate a parent bird has landed nearby, possibly with food.
As baby birds mature, they will gape when they perceive any opportunity that may lead to feeding, such as any adult bird nearby, even if that bird may not actually be their parent.
Learn more bird bill parts.
Also Known As:
Gape Flange, Rictus, Gaping (verb)
Photo – Hatchling Gape © Ian Soper