Anastomus oscitans
Silhouette: PhyloPic
In 3 days ~40% in a week ~70%
The Asian openbill or Asian openbill stork (Anastomus oscitans) is a large wading bird in the stork family Ciconiidae. This distinctive stork is found mainly in the Indian subcontinent and Southeast Asia. It is greyish or white with glossy black wings and tail. Adults have a gap between the arched upper mandible and recurved lower mandible which is thought to be an adaptation that aids in the handling of snails, their main prey. Young birds are born without this gap. Although resident within their range, they make long distance movements in response to weather and food availability.
The Asian openbill was described by the French polymath Georges-Louis Leclerc, Comte de Buffon in 1780 in his Histoire Naturelle des Oiseaux from a specimen collected in Pondichery, India. The bird was also illustrated in a hand-coloured plate engraved by François-Nicolas Martinet in the Planches Enluminées D'Histoire Naturelle which was produced under the supervision of Edme-Louis Daubenton to accompany Buffon's text. Neither the plate caption nor Buffon's description included a scientific name but in 1783 the Dutch naturalist Pieter Boddaert coined the binomial name Ardea oscitans in... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Kaziranga National Park | 🇮🇳 India | |
| 2 | Yala National Park | 🇱🇰 Sri Lanka | |
| 3 | Chitwan National Park | 🇳🇵 Nepal | |
| 4 | Manas National Park | 🇮🇳 India | |
| 5 | Minneriya National Park | 🇱🇰 Sri Lanka | |
| 6 | Wilpattu National Park | 🇱🇰 Sri Lanka | |
| 7 | Keoladeo National Park | 🇮🇳 India | |
| 8 | Ranthambore National Park | 🇮🇳 India | |
| 9 | Satpura National Park | 🇮🇳 India | |
| 10 | Nagarhole National Park | 🇮🇳 India | |
| 11 | Royal Bardia National Park | 🇳🇵 Nepal | |
| 12 | Udawalawe National Park | 🇱🇰 Sri Lanka | |
| 13 | Sundarbans National Park | 🇮🇳 India | |
| 14 | Gir National Park | 🇮🇳 India | |
| 15 | Bandipur National Park | 🇮🇳 India | |
| 16 | Kaeng Krachan National Park | 🇹🇭 Thailand | |
| 17 | Khao Yai National Park | 🇹🇭 Thailand | |
| 18 | Kanha National Park | 🇮🇳 India | |
| 19 | Mudumalai National Park | 🇮🇳 India | |
| 20 | Bandhavgarh National Park | 🇮🇳 India | |
| 21 | Periyar National Park | 🇮🇳 India | |
| 22 | Sinharaja Forest Reserve | 🇱🇰 Sri Lanka | |
| 23 | Royal Manas National Park | 🇧🇹 Bhutan | |
| 24 | Doi Inthanon National Park | 🇹🇭 Thailand | |
| 25 | Jim Corbett National Park | 🇮🇳 India |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Savar | 🇧🇩 Bangladesh | |
| 2 | Bangkok | 🇹🇭 Thailand | |
| 3 | Vijayawada | 🇮🇳 India | |
| 4 | Tamluk | 🇮🇳 India | |
| 5 | Patna | 🇮🇳 India | |
| 6 | Kolkata | 🇮🇳 India | |
| 7 | Vasai-Virar | 🇮🇳 India | |
| 8 | Madurai | 🇮🇳 India | |
| 9 | Berhampore | 🇮🇳 India | |
| 10 | Surat | 🇮🇳 India |
Possible
About 20% of wildlife watchers report an Asian Openbill Stork sighting in Udawalawe National Park on a given day, based on 94 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 99th most-seen of the 166 birds we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.
June and September
In those months about 30% of wildlife watchers report an Asian Openbill Stork in Udawalawe National Park on a given day, against about 10% in July–August and November–December, the lowest months. Those are among Udawalawe National Park's driest months, with about 80 mm of rain a month against 330 mm in November.
Between 2 and 5 am
Across all the parks we cover, that three-hour window holds the most Asian Openbill Stork sightings with a recorded time, and about 6 in 10 of them come between 6 am and 6 pm: it is most active around dawn and dusk.
12th of 25
Of the 25 parks where we can rate Asian Openbill Stork sightings, Udawalawe National Park ranks 12th at about 20%. The best odds are in Kaziranga National Park (India, about 80%), Yala National Park (Sri Lanka, about 60%) and Chitwan National Park (Nepal, about 50%). All parks ranked.
Same family: Ciconiidae
The closest relatives of the Asian Openbill Stork that you can see in Udawalawe National Park (family Ciconiidae, Storks) are Painted Stork (about 60%), Asian Woolly-necked Stork (about 30%) and Lesser Adjutant (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Asian Openbill Stork is recorded against all the birds logged in Udawalawe National Park (94 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
