Some nests are flimsy platforms of twigs, occasionally placed on unused rat nests or on an accumulation of litter in a crotch or tangle of vines. More typically, nests are built on a bare forking tree branch or near the top of a bamboo stalk. The plain pigeon lays only one egg, but a female has been observed to produce three broods in a year. The minimum observed incubation period is 18 days. The mean fledging period at eight nests was 23 days.
Chicks are dependent on the adults for several days after fledging.
Because of the very close nest attendance typical of the species, it suffers few losses of eggs and young to predators. Apparently, flocking can occur at any time food is locally abundant. Adult pigeons congregate in small flocks for feeding and drinking during the breeding season. Larger aggregations regularly form for roosting and feeding in the fall. A captive flock was established at the University of Puerto Rico's Humacao Campus in 1984.