New World vultures | Cathartidae

Nieuwewereldgieren | Buitres del Nuevo Mundo

This family was long grouped with the storks on the strength of shared outward traits, but more recent DNA evidence places it closer to the diurnal birds of prey; what does unite the family is a sense of smell unusually keen for a bird. The family lacks the muscles in the voice box that most birds use to produce sound, so its vocal repertoire is limited to hoarse hisses and grunts rather than calls or song. When overheated or threatened, the birds spray their own legs with liquid droppings; the evaporation cools the body, and the dried layer also protects the skin from bacteria picked up while walking through carrion. An intruder that gets too close is driven off not with the bill or claws but with a forceful, well-aimed jet of vomit, which has the added benefit of leaving the bird light enough to take off quickly.