Ajay Kumar at 21:39, 30 August 2023

2023-08-30T21:39:11Z

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{{Short description|Species of bird}}
{{Speciesbox
| name = Indian grey hornbill
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 12 November 2021">{{cite iucn |author=BirdLife International |date=2020 |title=''Ocyceros birostris'' |volume=2020 |page=e.T22682429A184951065 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22682429A184951065.en |access-date=12 November 2021}}</ref>
| image = Indian Grey Hornbill I IMG 4051.jpg
| image2 = Greyhornbill.ogg
| image2_caption = A male bird feeding the female at a nest in [[Punjab, India|Punjab]], and a recording made in [[Maharashtra]], both in [[India]]
| genus = Ocyceros
| species = birostris
| authority = ([[Giovanni Antonio Scopoli|Scopoli]], 1786)
| synonyms = ''Lophoceros birostris''<br/>''Tockus birostris''<br/>''Ocyceros ginginianus''<br/>''Meniceros birostris''
}}

The '''Indian gray hornbill''' ('''''Ocyceros birostris''''') is a common [[hornbill]]<ref>{{cite book|author=NiF Team|title=Things to Know About Hornbills|publisher=Nature inFocus|url=https://www.natureinfocus.in/animals/10-things-you-need-to-know-about-hornbills}}</ref> found on the [[Indian subcontinent]]. It is mostly [[arboreal]] and is commonly sighted in pairs. It has grey [[feather]]s all over the body with a light grey or dull white belly. The horn is black or dark grey with a [[:wikt:casque|casque]] extending to the point of curvature of the horn. It is one of the few hornbill species found in urban areas in many cities where they are able to make use of large trees in avenues.

==Description==
The Indian grey hornbill is a medium-sized hornbill, measuring around {{convert|61|cm|in|abbr=on}} in length.<ref name="hbk" /> The upper parts are greyish brown and there is a slight trace of a pale [[supercilium]]. The ear coverts are darker. The flight feathers of the wing are dark brown with a whitish tip. The tail has a white tip and a dark subterminal band. They have a red iris and the eyelids have eyelashes. The casque is short and pointed.<ref name="whistler">{{cite book|pages= 306–307| url=https://archive.org/stream/popularhandbooko033226mbp#page/n355/mode/2up |title=Popular handbook of Indian birds| author=Whistler, Hugh|edition=4th|publisher=Gurney and Jackson, London|year= 1949|isbn= 1-4067-4576-6}}</ref>

The male has a larger casque on a dark bill, and the [[Culmen (bird)|culmen]] and lower mandible are yellowish. The bare skin around the eye is dark in the male, but sometimes pale reddish in females.<ref>{{cite journal| author=Pittie, A.| journal= J. Bombay Nat. Hist. Soc.|title=A Note on the Circumorbital Skin Colour of Indian Grey Hornbill ''Ocyceros birostris''|year=2003| volume=100|issue=1| pages=141–142|url=https://biodiversitylibrary.org/page/48602715}}</ref> The female has a more yellowish bill with black on the basal half and on the casque.<ref name="hbk">{{cite book|author1=Ali, S. |author2=S. D. Ripley|year=1983 |title=Handbook of the Birds of India and Pakistan. Volume 4.|edition=2nd|publisher=Oxford University Press|place=New Delhi|pages=130–131}}</ref><ref name="pcr">{{cite book |author1= Rasmussen PC |author2=JC Anderton | year=2005| title=Birds of South Asia: The Ripley Guide. Volume 2|pages=272–273| publisher= Smithsonian Institution & Lynx Edicions}}</ref><ref>{{cite book|author=Baker, ECS|title=Fauna of British India. Birds. Volume 4 |edition=2nd |publisher=Taylor and Francis| place=London|pages=301–302 |url= https://archive.org/stream/BakerFbiBirds4/BakerFBI4#page/n331/mode/1up}}</ref>
The juveniles lack the casque, and the bare skin around the eye is dull orange.<ref>{{cite journal| author=Kasambe, R.| author2=Charde, P.| author3=Tarar, J. L.| author4=Pimplapure. A.| name-list-style=amp|year=2012| volume=7|issue=6| pages=165|title=Sub-orbital skin- and eye colour of young Indian Grey Hornbills Ocyceros birostris in Central India.|journal=Indian Birds}}</ref>

==Distribution==

The species is found mainly on the plains up to about {{convert|2000|ft|abbr=on}}. It is found from the foothills of the Himalayas southwards, bounded to the west by the Indus system and to the east by the [[Ganges Delta]]. It may make local movements in the drier western region. It is found even in cities that have old avenue trees.<ref name=pcr/> The species has been observed, usually in pairs, in Dharamsala town (Himachal Pradesh) at about 1500 to 1600 masl during summer and in the rainy season (May to September, 2017). and does not overlap much with the [[Malabar grey hornbill]] of the Western Ghats.<ref name=whistler/><ref>{{cite journal|author1=Amladi, SR |author2=Daniel, JC |year=1973| title= Occurrence of the Common Grey Hornbill (''Tockus birostris'') in Bombay city| journal= J. Bombay Nat. Hist. Soc.| volume=70|issue=2|pages=378–380|url=https://biodiversitylibrary.org/page/48290365}}</ref>

==Behaviour and ecology==

The call is a squealing call somewhat like that of a [[black kite]]. The flight is heavy and involves flapping interspersed with glides. They are found in pairs or small groups.<ref name=whistler/>

The nesting season is April to June and the clutch varies from one to five very symmetrical white eggs. Indian grey hornbills usually nest in tree hollows on tall trees. An existing hollow may be excavated further to suit. The female enters the nest hollow and seals the nest hole, leaving only a small vertical slit through which the male feeds her. The nest entrance is sealed by the female using its excreta and mud-pellets supplied by the male.<ref>{{cite book|page=141|title=Fauna of British India. Birds Volume 3|author=Blanford, WT| year=1895|publisher=Taylor and Francis, London|url=https://archive.org/stream/birds00blangoog#page/n159/mode/1up/ }}</ref><ref>{{cite journal|author=Hall, Eleanor Frances |year=1918| title= Notes on the nidification of the Common Grey Hornbill (''Lophoceros birostris'')| journal= J. Bombay Nat. Hist. Soc. |volume= 25| issue=3|pages=503–505|url=https://biodiversitylibrary.org/page/5454388}}</ref> While inside the nest, the female moults her flight feathers and incubates the [[Egg (biology)|egg]]s. The male provides the nest inmates with a steady supply of bark pieces to ensure that the excreta is removed from the nest by absorption and adsorption and to help maintain the micro-climate within the next cavity. <ref> {{cite journal|author=Charde, Praveen |author2=Kasambe, Raju |author3=Pimplapure, Anil|author4=Tarar, Jeevan L|year=2011| title= NEST SANITATION IN INDIAN GREY HORNBILL IN CENTRAL INDIA| journal= The Raffles Bulletin of Zoology|issue=24| pages=65-67 |url= https://www.researchgate.net/publication/279757601_NEST_SANITATION_IN_INDIAN_GREY_HORNBILL_IN_CENTRAL_INDIA}} </ref> The regrowth of the female's feathers coincides with the maturity of the chicks, at which point the nest is broken open.<ref name=whistler/><ref>{{cite journal|author=Finlay, JD |year=1929| title= The nesting habits of the Northern Grey Hornbill ''Lophoceros birostris'' | journal= J. Bombay Nat. Hist. Soc. |volume=33| issue=2| pages=444–445|url=https://biodiversitylibrary.org/page/47860279}}</ref><ref>{{cite book|pages=74–76| url= https://archive.org/stream/cu31924000044994#page/n95/mode/2up | title= The nests and eggs of Indian bird volume 3|author=Hume, AO| year=1889| publisher=R H Porter, London}}</ref>

A study at a nest near [[Mumbai]] noted that the key fruiting trees on which the hornbills fed were ''[[Streblus asper]]'', ''[[Cansjera rheedii]]'', ''[[Carissa carandas]]'', ''[[Grewia tiliaefolia]]'', ''[[Lannea coromandelica]]'', ''Ficus'' spp., ''[[Sterculia urens]]'' and ''[[Securinega leucopyrus]]''. They are also known to take molluscs, scorpions, insects, small birds (they have been recorded removing and possibly preying on [[rose-ringed parakeet]] chicks<ref>{{cite journal|author=Newnham, A |year=1911| title= Hornbills devouring young Paroquets|journal= J. Bombay Nat. Hist. Soc. |volume= 21|issue=1|pages= 263–264|url=https://biodiversitylibrary.org/page/30150940}}</ref>) and reptiles in their diet<ref>{{cite journal|author1=Patil, Neelam |author2=Chaturvedi, Naresh |author3=Hegde, Vithoba |year=1997 | title= Food of Common Grey Hornbill ''Tockus birostris'' (Scopoli)| journal= J. Bombay Nat. Hist. Soc. | volume=94|issue=2|pages=408–411|url=https://biodiversitylibrary.org/page/48601770}}</ref> They are known to feed on the fruits of ''[[Thevetia peruviana]]'', which are known to be toxic to many vertebrates.<ref>{{cite journal|author= Neelakantan, KK |year=1953| title= Common Grey Hornbill (''Tockus birostris'') eating fruits of the Yellow Oleander (''Thevetia neriifolia'')| journal= J. Bombay Nat. Hist. Soc.|volume=51|issue=3|page=738|url=https://biodiversitylibrary.org/page/48202898}}</ref>

They are almost completely arboreal, but very rarely descend to the ground to pick up fallen fruits, to dust bathe,<ref>{{cite journal| author=Santharam, V |year=1990 |title= Common Grey Hornbill ''Tockus birostris'' (Scopoli) dust bathing| journal= J. Bombay Nat. Hist. Soc. |volume= 87| issue=2 | pages=300–301|url=https://biodiversitylibrary.org/page/48807014}}</ref> or to pick up mud pellets to seal the nest cavity during the nesting period.<ref name="Charde">{{cite journal|author=Charde, P.|author2=Kasambe, R.|author3=Tarar, J.L.|name-list-style=amp|year=2011|title=Breeding behaviour of Indian Grey Hornbill ''Ocyceros birostris'' in Central India|journal=The Raffles Bulletin of Zoology|volume=24|pages=59–64|url=http://rmbr.nus.edu.sg/rbz/biblio/s24/s24rbz059-064.pdf|access-date=2012-01-04|archive-date=2014-03-21|archive-url=https://web.archive.org/web/20140321130524/http://rmbr.nus.edu.sg/rbz/biblio/s24/s24rbz059-064.pdf|url-status=dead}}</ref> They indulge in various social activities, including bill-grappling and aerial jousting.<ref>{{cite journal|author= Kasambe, R.|author2= Charde, P.|author3= Yosef, R.|name-list-style= amp |year=2011| title= Aerial jousting and bill-grappling in Indian Grey Hornbill (''Ocyceros birostris'')| journal=Acta Ethologica| volume= 14| issue=1| pages=13–15|doi=10.1007/s10211-010-0085-2|s2cid= 1691573}}</ref>
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==Gallery==
<gallery>
Indian Grey Hornbill I2 IMG 9029.jpg|Individual with a shorter casque, either a juvenile or female
Indian Grey Hornbill I IMG 9017.jpg|At [[Uttarakhand]], [[India]]
Indian grey hornbill foraging.jpg|In [[Janakpur]], [[Nepal]]
Indian GreyHornbill.JPG|A pair (female right and male at left) at [[Mohali]], [[Punjab, India|Punjab]], northern India
Indian Grey Hornbill at twilight.jpg|Indian Grey Hornbill in [[Pune]]. Note the casque, and the distinctive tail feathers.
</gallery>

==References==
{{Commons category|Ocyceros birostris}}
{{Reflist|2}}


{{Taxonbar|from=Q223574}}

[[Category:Ocyceros|Indian grey hornbill]]
[[Category:Birds of South Asia]]
[[Category:Birds described in 1786|Indian grey hornbill]]

Indian grey hornbill - Revision history

Ajay Kumar at 21:39, 30 August 2023