Breeding: In Trinidad, breeding records indicate that breeding occurs between January and August (ffrench 1991). In Costa Rica, breeding occurs between February and October (Skutch 1954, Stiles and Skutch 1989); in Panama breeding is restricted to the months of March and April (Isler and Isler 1999). One breeding pair can successfully rear one, two or even three broods in one mating season; in Costa Rica, one female began laying a second clutch only 18 days after the first brood fledged (Skutch 1954).
Nest building is primarily completed by the female, but males will bring nesting materials during early construction. Nests are cup-shaped, well-concealed, and covered with moss, rootlets, and various screening foliage. Bay-headed Tanager nests tend to be constructed off the ground in trees and vines, sometimes as high as 7.6 m off the ground, though typically nests remain 2.4-4.6 m off the ground in Trinidad (ffrench 1991) and 4.5-5.5 m of the ground in Costa Rica (Stiles and Skutch 1989).
Eggs: Eggs are generally a dull white color, spotted with a brown wreath at the thicker end of the egg (Stiles and Skutch 1989, ffrench 1991, Isler and Isler 1999). Clutch size: 2 eggs are laid on consecutive days (Skutch 1954).
Incubation: The female Bay-headed Tanager is solely responsible for incubating the eggs. She incubates both eggs for 13-14 days (Skutch 1954).
Parental care-condition at hatching, growth and development, brooding, feeding, etc.: Nestling period lasts 15-16 day after hatching; both parents care and feed their young (Skutch 1954).