Birds look after their young from hatching to fledging. One or both the parents undertake these duties that include incubation, brooding and teaching the fledglings to be independent.
In over 220 species out of the total 9,000 species of birds in the world, cooperative breeding has been documented.
Cooperative breeding involves the fledglings remaining with the parents once they are capable of fending for themselves. They stay behind for a year or more to help their parents raise subsequent broods. Assistance involves mainly feeding the young. Sometimes it may include incubation and territorial defence or defence against predators.
There are three basic types of cooperative breeding. The most common, known as singular breeding, is where the breeding pair is helped by a number of juvenile birds. Less common is plural breeding. Here, a group of two or more breeding pairs, in as many nests, are helped by juveniles. The third type or joint breeding, is where more than one female lay their eggs in the same nest and all members of the group help rear the enlarged brood.
Cooperative breeding has been reported in the Grey-crowned Babbler (Pomatostomus temporalis), Chestnut-bellied (Lamprotornis pulcher) and Superb Starlings (Lamprotornis superbus), Pied Kingfisher (Ceryle rudis), Galapagos Mockingbird (Nesomimus parvulus), Ostriches (Struthio camelus)… and so on.
A recent paper by Pierce et al. (2007) documents cooperative breeding in the Puff-throated Bulbul (Alophoixus pallidus) at Khao Yai National Park, Thailand.
Among the gregarious species of bee-eaters, the majority of broods in the colony are brought up by their parents assisted by up to five helpers (Fry & Fry, 1992).
I am sure at least one or a few local birders must have observed cooperative breeding among local species. After all, birders have been looking at local birds for decades now. One report I know is the House Crows, posted earlier.
Can local birdwatchers keep a lookout for cooperative breeding when out in the field? We look forward to posting such observations in the future.
1. Fry, C.H. & Fry, K. (1992). Kingfishers, bee-eaters and rollers. New Jersey: Princeton University Press.
2. Pierce, A.J., Tokue, K., Pobprasert, K. & Sankamethawee, W. (2007). Cooperative breeding in Puff-throated Bulbul Alophoixus pallidus in Thailand. Raffles Bull. Zool 55:187-9.