Reproductive biology

Most barbets have breeding territories and are monogamous, and some pair for life. They proclaim and defend a territory by singing, but their songs may be quite varied: some have 10 or 12 particular calls that are used as song, often in complex male-female duets. Often other birds apart from the breeding pair join in the chorus of songs, apparently serving to strengthen the effect of the song by communicating the size and therefore strength of the group.

Various displays include exposure of color patches on the head, wings, rump, tail, and bill, with feathers being erected to maximize the effect. If there is a difference between the sexes, the male's special color patches are used in such displays. Pairs of barbets focus their courtship activity around the hole that will serve as their nest, and often preen one another. They are long-lived birds with strong pair bonds, supported and cemented by activities such as mutual grooming, which are maintained all year. The pair typically mates for life, so breeding season courtship displays are rather limited, being required only to synchronize breeding condition between male and female.

The nest is in a hole in a tree, usually freshly excavated. Smaller species nest in dead or dying branches, typically digging in from beneath a horizontal bough. Barbets tend to make larger entrance holes than woodpeckers of a similar size. The hole enters a vertical shaft ending in a slightly widened chamber in which the eggs are laid. In more social species several "helpers" may be involved in digging the nest hole over a number of weeks, although in some the helpers at the nest are not involved in the excavation. Wood chips are usually carried away, sometimes being swallowed and then regurgitated elsewhere, presumably to prevent telltale signs from accumulating beneath the tree, giving clues of the nest's whereabouts to predators. The eggs are still not described for many species and incubation and fledging periods are generally little known. Like those of woodpeckers, barbet eggs are, however, always pure white and the clutch size up to six (typically three) in African barbets, two to five (again, most often three) in South American species. Incubation averages around 15 days—12 days for the smallest and up to 19 days for larger species. Once the chicks are hatched, adult barbets keep the nest exceptionally clean in most cases, probably swallowing rather than carrying away the chicks' droppings. Nestlings of small species leave the nest after 17 to 23 days, larger ones remaining as long as 30

or 40 days, notably long periods for such modestly sized birds. Helpers (sometimes young of the pair from previous years) assist the pair in feeding the chicks in some species, while many are strictly territorial and only the breeding pair is involved.

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