Breeding

In its native geographic range, south of the equator in southwestern Ecuador, nesting occurs January through March, during the rainy season, and a single clutch of two to four eggs is laid (Best et al. 1995). The nesting activity of A. erythrogenys decreases dramatically in years when high rainfall overlaps the nesting season during the January through April rainy season in the Peruvian range (Chavez-Riva 1994). In the native range in Peru, A. erythrogenys only nested as solitary (noncolonial) pairs in the largest tree species present within valleys (Chaves-Riva 1994). As secondary cavity nesters that do not create their own next cavities ,they are dependent upon woodpeckers (Piciformes) and/or old trees with broken branches for nesting cavities (Chaves-Riva 1994).  Native range cliff nesting in this species is little documented with only one record from Ecuador of colonial nesting in a cliff face in the month of May 1898 (Goodfellow 1900); populations in Hawai'i, however, appear to exclusively colonially nest in inland (not coastal) rock cliffs and not in tree cavities (Kalodimos, personal observation).

On O'ahu, Hawai'i, A. erythrogenys nests colonially on inland valley rock cliffs in tropical dry forest habitat. Chosen cliff sites where (known) successful nesting takes place have always been east facing. Pairs defend the immediate opening to their rock crag but ignore individuals nearby. Colonially nesting individuals usually foraged together, departing the cliff site together, going to the same foraging locations and returning together as a single flock. Nonincubating or brooding members of colonially cliff nesting pairs did not overnight at the nestinng cliff, but instead, returned to the communal evening roost. Pairs began to claim ownership of cliff cavities as early as March and by late June/early July individual pairs had taken up daily residence of cavities. Egg laying began the last week of June and the first fledgings occurred in late August and the first week of September. One pair began laying as late as August 10 and another in the same cliff was on recently hatched chicks about the 20th of August. The latest nest fledging occurred the week of 4 December in 2006. Chicks fledged in late August by one pair were seen begging and being fed by their parents as late as late November indicating a food dependency period (or supplimental) of at least three months post-fledging. Pairs on O'ahu, Hawai'i only have been seen with up to two fledglings but a pair in a population in San Francisco, California, USA was seen with four fledglings (Bittner 2004).