Cathartes aura

Forested and open situations, more commonly in the latter, from lowlands to mountains (AOU 1983). May roost in large flocks at night in trees; roosts often near or over water. In Pennsylvania, selected large conifers for mid-winter roost (Wright et al. 1986).

Eggs are laid in caves (especially in West); on cliffs; in hollow logs, trees, or stumps (tree-cavity nesting formerly more common); on ground in dense shrubbery (especially in eastern U.S.); sometimes in/under abandoned building in woods (Jackson 1983, Palmer 1988); sometimes in abandoned hawk nest (Hilty and Brown 1986). In Pennsylvania/Maryland, nested in areas that were roadless, forested, and undeveloped (Coleman and Fraser 1989).

Roosts singly or in groups. Average distance between communal roost and feeding site was 8 km in Maryland/Pennsylvania (Coleman and Fraser 1987). Mean summer range of two known breeders was 6942 hectares; 90% of locations were within 10 kilometers of roost (Kirk and Mossman 1998). Roosts may be temporary (at a food source), seasonal (spring-fall), or permanent (peak numbers in early winter) (Palmer 1988). Human disturbance and canid predation may be significant causes of nest failure in the eastern U.S. (Coleman and Fraser 1989).

Clutch size is usually 2. Incubation lasts 5-6 weeks, by both sexes. Young first fly at about 9 weeks. Family may stay together several months after young fledge. Does not renest if clutch is lost.