Editing Asian openbill (section)

==Breeding==
[[File:Asian open-billed storks (Anastomus oscitans) juvenile on right.jpg|thumb|right|Juvenile on the right. The gap between the mandibles develops with age.]]
The breeding season is after the rains, during July to September in northern India and Nepal, and November to March in southern India and Sri Lanka.<ref name=":1" /> They may skip breeding in drought years. The Asian openbill breeds colonially, building a rough platform of sticks often on half-submerged trees (often ''Barringtonia'', ''Avicennia'' and ''Acacia'' species), typically laying two to four [[bird egg|eggs]]. The nesting trees are either shared with those of [[egret]]s, [[cormorant]]s and darters, or can be single-species colonies like in lowland Nepal.<ref name=":2" /> Nesting colonies are sometimes in highly disturbed areas such as inside villages and on trees located in crop fields.<ref>{{cite journal|title=The effect of human interference on the nesting of the openbill stork Anastomus oscitans at the Raiganj wildlife sanctuary, India| vauthors=Datta T, Pal BC | journal= Biological Conservation|volume= 64| issue= 2| year=1993| pages=149–154| doi=10.1016/0006-3207(93)90651-G  | bibcode=1993BCons..64..149D }}</ref><ref name=":1" /> Colonies are also found in small cities such as Udaipur in Rajassthan, India, which has several large artificial wetlands within the city limits.<ref>{{Cite journal |last1=Mehta |first1=Kanishka |last2=Koli |first2=Vijay K. |last3=Kittur |first3=Swati |last4=Sundar |first4=K. S. Gopi |date=2024 |title=Can you nest where you roost? Waterbirds use different sites but similar cues to locate roosting and breeding sites in a small Indian city |journal=Urban Ecosystems |volume=27|issue=4 |pages=1279–1290 |doi=10.1007/s11252-023-01454-5 |bibcode=2024UrbEc..27.1279M }}</ref> In lowland Nepal, 13 colonies found in an agricultural landscape had an average colony size of 52, ranging from 5 nests to 130 nests.<ref name=":1" /> The majority of these colonies were located on ''Bombax ceiba'' trees, with much fewer located on ''Ficus religiosa'' and ''Dalbergia sissoo'' tree species. Asian openbills preferred trees that were much taller and bigger than trees that were available on the landscape, and selectively used wild and native tree species entirely avoiding species that were important for resources such as fruits (e.g. ''Mangifera indica'') despite such trees being much more common.<ref name=":3">{{Cite journal|last1=Koju|first1=Roshila|last2=Maharjan|first2=Bijay|last3=Gosai|first3=K.R.|last4=Kittur|first4=Swati|last5=Sundar|first5=K.S. Gopi|title=Ciconiiformes nesting on trees in cereal-dominated farmlands: the importance of scattered trees for heronries in lowland Nepal|journal=Waterbirds|year=2020|volume=42|issue=4|pages=355–365|doi=10.1675/063.042.0401|s2cid=210861485|doi-access=free}}</ref> Religious beliefs have secured important trees such as ''Ficus'' species, and agro-forestry has secured the most preferred species, ''Bombax ceiba'', that Asian openbills prefer to locate colonies in lowland Nepal.<ref name=":3" /> The [[bird nest|nests]] are close to each other leading to considerable aggressive interactions between birds on neighbouring nests. Both parents take turns in incubation, the eggs hatching after about 25 days. The chicks emerge with cream coloured down and are shaded by the loosely outspread and drooped wings of a parent.<ref name=hbk/>

[[File:Asian Openbill in Nepal.jpg|thumb|A pair copulating ([[Nepal]])]]
Initiation of nests in lowland Nepal was highly synchronized, with colonies started during July and August. Breeding success at nests in these colonies was impacted by proximity of colonies to human habitation, and the progression of the breeding season.<ref name=":0">{{Cite journal|last1=Sundar|first1=K.S. Gopi|last2=Koju|first2=Roshila|last3=Maharjan|first3=Bijay|last4=Marcot|first4=Bruce G.|last5=Kittur|first5=Swati|last6=Gosai|last7=Kamal Raj|date=2019|title=First assessment of factors affecting the breeding success of two stork species in lowland Nepal using Bayesian Network models|url=https://wildfowl.wwt.org.uk/index.php/wildfowl/article/view/2690/pdf_159 |journal=Wildfowl|volume=69|pages=45–69}}</ref> Colonies closer to human habitation had lower success, and colonies initiated later during the breeding season (when flooding of the rice fields had reduced to allow ripening of the crop) had lower success. Number of chicks that fledged from colonies located on trees in agricultural landscapes in lowland Nepal were similar to that observed in a protected, mangrove reserve in eastern India suggesting that agricultural areas are not always detrimental to large waterbirds such as Asian openbills.<ref name=":0" />

Nesting openbills in Nepal took an average of 27 minutes to return to nests with food for nestlings and fledglings.<ref name=":2">{{Cite journal|last1=Sundar|first1=K. S. Gopi|last2=Maharjan|first2=Bijay|last3=Koju|first3=Roshila|last4=Kittur|first4=Swati|last5=Gosai|first5=Kamal Raj|date=2016|title=Factors Affecting Provisioning Times of Two Stork Species in Lowland Nepal| journal=Waterbirds|volume=39|issue=4|pages=365–374|doi=10.1675/063.039.0406|doi-access=free}}</ref> The time taken to find food was most impacted by the location of wetlands around colonies, and the progression of the breeding season. Adults look the least time to return with food earlier in the season when the dominant rice crop was most flooded, and time increased as the rice ripened along with the drying out of the fields.<ref name=":2" /> Adult birds in Nepal provisioned chicks at nest with snails of the genus ''[[Filopaludina]]'' and ''[[Pila (gastropod)|Pila]].'' Hatchlings received 87-120 g/day of food, while older nestlings received 272-386 g/day of food.<ref>{{Cite journal |last1=Tamang |first1=Ganesh |last2=Katuwal |first2=Hem Bahadur |last3=Subba |first3=Asmit |last4=Singh |first4=Nanda Bahadur |date=2024 |title=Nutritional dynamics in early development of Asian Openbill: A study of hatchling and nestling feeding patterns |url=https://www.sciencedirect.com/science/article/pii/S2950509724000157 |journal=Ecological Frontiers |volume=44 |issue=4 |pages=726–732 |doi=10.1016/j.ecofro.2024.03.005 |issn=2950-5097|url-access=subscription }}</ref>

Like other storks, they are silent except for clattering produced by the striking of the male's [[beak|bill]] against that of the female during copulation. They also produce low honking notes accompanied by up and down movements of the bill when greeting a partner arriving at the nest.<ref name=pcr /><ref>{{cite journal|author= Kahl, M Philip |year=1970| title= Observations on the breeding of Storks in India and Ceylon| journal= J. Bombay Nat. Hist. Soc. |volume=67| issue=3|pages=453–461|url=https://www.biodiversitylibrary.org/page/47820044}}</ref><ref>{{cite journal|author=Mukhopadhyay, Anand |year=1980| title= Some observations on the biology of the Openbill Stork, ''Anastomus oscitans'' (Boddaert), in southern Bengal| journal=J. Bombay Nat. Hist. Soc.| volume=77| issue=1| pages=133–137|url=https://www.biodiversitylibrary.org/page/44708043}}</ref> Males may sometimes form polygynous associations, typically with two females which may lay their eggs in the same nest.<ref>{{cite journal| journal= The Auk | volume=112| issue=1| pages=257–260| year= 1995| title= Polygyny in the Asian Openbill (Anastomus oscitans)| vauthors= Datta T, Pal BC |url=http://sora.unm.edu/sites/default/files/journals/auk/v112n01/p0257-p0260.pdf| doi= 10.2307/4088788| jstor=4088788}}</ref>