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Bucerotiformes notes

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Breeding

Hornbills generally form monogamous pairs, although some species engage in cooperative breeding. The female lays up to six white eggs in existing holes or crevices, either in trees or rocks. The cavities are usually natural, but some species may nest in the abandoned nests of woodpeckers and barbets. Nesting sites may be used in consecutive breeding seasons by the same pair. Before incubation, the females of all Bucerotinae—sometimes assisted by the male—begin to close the entrance to the nest cavity with a wall made of mud, droppings and fruit pulp. When the female is ready to lay her eggs, the entrance is just large enough for it to enter the nest, and after she has done so, the remaining opening is also all but sealed shut. There is only one narrow aperture, big enough for the male to transfer food to the mother and eventually the chicks. The function of this behaviour is apparently related to protecting the nesting site from rival hornbills.[9] The sealing can be done in just a few hours, at most it takes a few days. Having sealed the nest it takes a further five days for the first egg to be laid. Clutch size varies from one or two eggs in the larger species to up to eight eggs for the smaller species. During the incubation period the female undergoes a complete and simultaneous moult. It has been suggested that the darkness of the cavity triggers a hormone involved in moulting.[10] Non-breeding females and males go through a sequential moult.[11] When the chicks and the female are too big to fit in the nest, the mother breaks out with the help of the male, then both parents feed the chicks.[1] In some species the mother rebuilds the wall, whereas in others the chicks themselves rebuild the wall unaided. The ground-hornbills are conventional cavity-nesters instead.

 

http://en.wikipedia.org/wiki/Hornbill

 

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01/03/2008 0000000

25/10/2009 500,000

28/02/2012 870,300

 


 

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01/01/2009 151,000

01/10/2010 562,291

24/09/2012 1,000,000

 

Credits Some of the maps, data, are from http://en.wikipedia.org/wiki/Main_Page               Data from Avibase