From Sasquatch Chronicles:
Hominid apes construct nests during the day or by night, primarily for resting. The nests are not built using instinct but through behavioural patterns which are learned by the young from their mother. Nest building is habitual behaviour, and nest-counts and faecal analysis at each nest site can be used to estimate hominid ape population counts and composition. In the case of orangutans and chimpanzees, social influences are probably essential for the animals to develop successful nesting-behaviour.
Gorillas construct nests for day and night use. Day nests tend to be simple aggregations of branches and leaves on the ground whilst night nests are more elaborate constructions usually on the ground but sometimes on trees, especially those of juveniles and females in areas submitted to a high poaching pressure. The nests may be 1 to 5 feet (0.30 to 1.52 m) in diameter and are constructed by individuals. Young animals nest with their mother but do not construct nests until three years of age, initially in close proximity to their mother. Gorilla nests are distributed randomly and the tree species used appears to be opportunistic.
Derek Randles from the Olympic Project discusses finding gorilla-like nest in Washington State and the research they are conducting.