Editing Hornbill (section)

==Behaviour and ecology==
Hornbills are [[Diurnality|diurnal]], generally travelling in pairs or small family groups. Larger flocks sometimes form outside the breeding season. The largest assemblies of hornbills form at some roosting sites, where as many as 2400 individual birds may be found.<ref name="Bil">{{Cite web|url=https://www.beautyofbirds.com/hornbills.html|title=Hornbills &#124; Beauty of Birds |date=16 September 2021}}</ref>

===Diet===
[[File:Buceros bicornis (female) -feeding in tree-8.jpg|thumb|Female [[great hornbill]] feeding on figs. Fruit forms a large part of the diet of forest hornbills.]]
Hornbills are [[omnivore|omnivorous]] birds, eating fruit, insects and small animals. They cannot swallow food caught at the tip of the beak as their tongues are too short to manipulate it, so they toss it back to the throat with a jerk of the head. While both open country and forest species are omnivorous, species that specialise in feeding on fruit are generally found in forests, while the more carnivorous species are found in open country.<ref name="HBW" /> Forest-dwelling species of hornbills are considered to be important seed dispersers.<ref>{{cite journal |title=Implications of long-distance movements of frugivorous rain forest hornbills |journal=Ecography |year=2002 |first1=Kimberley |last1=Holbrook |first2=Thomas B. |last2=Smith |first3=Britta D. |last3=Hardesty |volume=25 |issue=6 |pages=745–749 |doi=10.1034/j.1600-0587.2002.250610.x |bibcode=2002Ecogr..25..745H |citeseerx=10.1.1.598.3777}}</ref> Some hornbill species (e.g., [[Malabar pied-hornbill]]) even have a great preference for the fruits of the [[strychnine tree]] (''Strychnos nux-vomica''), which contain the potent poison [[strychnine]].<ref>Malabar Pied Hornbill | JLR Explore</ref>

Some hornbills defend a fixed [[territory (animal)|territory]].<ref name=EoB /> Territoriality is related to diet; fruit sources are often patchily distributed and require long-distance travel to find. Thus, species that specialise in fruit are less territorial.

===Breeding===
[[File:Britannica Hornbill Buceros bicornis.png|left|thumb|Male hornbill transfers a fig to the female.<ref>{{Cite EB1911|wstitle=Hornbill}}</ref>]]
[[File:Black-casqued hornbill male skeleton.jpg|thumb|Male black-casqued hornbill (''[[Black-casqued hornbill|Ceratogymna atrata]])'' on display at the [[Museum of Osteology]].]]
Hornbills generally form [[Monogamy in animals|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 [[woodpecker]]s and [[Capitonidae|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 her 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.<ref>{{cite journal|title=Nest intruders, nest defence and foraging behaviour in the Black-and-white Casqued Hornbill ''Bycanistes subcylindricus''|journal=Ibis |year=1988|first=Jan|last=Kalina|volume=131|issue=4 |pages=567–571|doi= 10.1111/j.1474-919X.1989.tb04791.x}}</ref> The sealing can be done in just a few hours; at most it takes a few days. After the nest is sealed, the hornbill takes another five days to lay the first egg. [[Clutch (eggs)|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.<ref>{{cite journal|author=Stonor, C. R.|year=1937|title=On the attempted breeding of a pair of Trumpeter Hornbills (''Bycanistes buccinator'') in the gardens in 1936; together with some remarks on the physiology of the moult in the female|journal=Proceedings of the Zoological Society of London, Series A |volume=107 |issue=Part 3 |pages=89–94|doi=10.1111/j.1469-7998.1937.tb08502.x}}</ref> Non-breeding females and males go through a sequential moult.<ref>{{cite journal|author=Moreau, RE|year=1937|title=The comparative breeding biology of the African Hornbills (Bucerotidae)|url=http://www.kalro.org:8080/repository/bitstream/0/4920/1/REPRINTS%20COLLECTION%2036%20Split%202.pdf|journal=Proceedings of the Zoological Society of London, Series A|volume=107|issue=Part 3|pages=331–346|doi=10.1111/j.1096-3642.1937.tb00815.x|access-date=2018-03-06|archive-url=https://web.archive.org/web/20180306142227/http://www.kalro.org:8080/repository/bitstream/0/4920/1/REPRINTS%20COLLECTION%2036%20Split%202.pdf|archive-date=2018-03-06|url-status=dead}}</ref> When the chicks and the female are too big to fit in the nest, the mother breaks out the nest and both parents feed the chicks.<ref name=EoB /> In some species the mother rebuilds the wall, whereas in others the chicks rebuild the wall unaided. The ground hornbills do not adopt this behaviour, but are conventional cavity-nesters.<ref name=EoB />

===Associations with other species===
A number of hornbills have associations with other animal species. For example, some species of hornbills in Africa have a [[Mutualism (biology)|mutualistic relationship]] with [[dwarf mongoose]]s, foraging together and warning each other of nearby [[birds of prey]] and other predators.<ref>{{cite journal |last1=Anne |first1=O. |last2=Rasa |first2=E. |date=June 1983 |title=Dwarf mongoose and hornbill mutualism in the Taru desert, Kenya |journal=Behavioral Ecology and Sociobiology |volume=12 |issue=3 |pages=181–90 |doi=10.1007/BF00290770|bibcode=1983BEcoS..12..181A |s2cid=22367357}}</ref> Other relationships are [[Commensalism|commensal]], for example following monkeys or other animals and eating the insects flushed up by them.<ref>{{cite journal |title=Black Hornbill ''Abthracoceros malayanus'' following Gibbons in central Borneo |journal=Ibis |year=1998 |first1=Mauro |last1=Gaietti |first2=Kim |last2=McConkey |volume=140 |issue=4 |pages=686–687 |doi=10.1111/j.1474-919X.1998.tb04716.x}}</ref>