Term used to describe young birds that are totally helpless (usually featherless, with eyes closed, and totally dependent on their parents) for a period after hatching. Contrast this with precocial young. At hatching, Purple Martin nestlings are altricial. Their eyes don't open until they are about 8 days old, they don't get a covering of body feathers until about 12 days of age, and they are unable to keep their own body temperatures up without the brooding of their parents until they are about 15 to 20 days old.
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching. See also: precocial
Refers to young mammals (e.g. rats, mice, cats, dogs, giant pandas) that are helpless at birth. Their eyes and ears are sealed, and they cannot walk, maintain their body temperature, or excrete without assistance. (Compare " precocial".) ( Allaby 1991)