Generally used for display purposes, crests can be fixed or erectile, depending on the species. For example, Cockatoos and cockatiels possess crests which may be raised or lowered at will. Their crests are used to communicate with fellow members of their species, or as a form of defence to frighten away other species that approach too closely.
The crest is made up of semiplume feathers: a long rachis with barbs on either side. These are plumulaceous feathers, meaning that they are soft and bendable. In birds, these semiplumes are common along the head, neck, and upper back, and may be used for buoyancy and sensing vibrations.
FOSSIL FEATHERS FROM THE HAWAIIAN FLIGHTLESS IBIS (APTERIBIS SP.): PLUMAGE COLORATION AND SYSTEMATICS OF A PREHISTORICALLY EXTINCT BIRD
Sep 01, 2011; ABSTRACT - A nearly complete skeleton of an adult Hawaiian flightless ibis (Apteribis sp.) was recovered from a vaulted dry lava...
Birds consumed by the invasive Burmese python (Python molurus bivittatus) in Everglades National Park, Florida, USA.
Mar 01, 2011; The Burmese python (Python molurus bivitattus) is now well established in Everglades National Park (ENP), Florida (Snow 2006,...