The clutch of the American yellow warbler is 3–6 (typically 4–5, rarely 1–2) eggs. Incubation usually takes 11 days, sometimes up to 14. The nestlings weigh on average, are brooded for an average 8–9 days after hatching, and leave the nest the following day or the one thereafter. The mangrove warbler, on the other hand, has only 3 eggs per clutch on average and incubates some 2 days longer. Its average post-hatching brooding time is 11 days. Almost half of the parents (moreso in the mangrove warbler than the American yellow warbler) attend the fledglings for two weeks or more after these leave the nest. Sometimes the adults separate early, each accompanied by one to three of the young.