Sterna aurantia
Silhouette: Sharon Wegner-Larsen · PhyloPic
In 3 days ~30% in a week ~50%
The river tern or Indian river tern (Sterna aurantia) is a tern in the family Laridae, the largest species currently included in the genus Sterna of typical terns. It is a resident breeder along inland rivers from Pakistan east through the Indian subcontinent, to Myanmar, Thailand, and Cambodia, where it is uncommon. Unlike most Sterna terns, it is almost exclusively found on freshwater, rarely venturing even to tidal creeks.
It is a medium-large tern, 38–46 cm long with an 80–85 cm wingspan, distinctly larger than any other species in Sterna and more comparable in size to a Sandwich tern (Thalasseus sandvicensis) or a lesser crested tern (T. bengalensis). It has dark grey upperparts, white or very pale grey underparts, a forked tail with long flexible streamers, and long pointed wings with pale grey primaries. The bill is stout for a tern, bright yellow in summer and duller yellow with a dusky tip in winter, and the legs bright red. It has a black cap in breeding plumage, which is more extensive than in other Sterna terns, extending well below the eye instead of barely or not below the eye. In winter the cap is greyish white, flecked and streaked with black, with... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Ranthambore National Park | 🇮🇳 India | |
| 2 | Satpura National Park | 🇮🇳 India | |
| 3 | Kaziranga National Park | 🇮🇳 India | |
| 4 | Gir National Park | 🇮🇳 India | |
| 5 | Keoladeo National Park | 🇮🇳 India | |
| 6 | Nagarhole National Park | 🇮🇳 India | |
| 7 | Jim Corbett National Park | 🇮🇳 India | |
| 8 | Periyar National Park | 🇮🇳 India | |
| 9 | Bandipur National Park | 🇮🇳 India | |
| 10 | Bandhavgarh National Park | 🇮🇳 India |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Rajkot | 🇮🇳 India | |
| 2 | Kota | 🇮🇳 India | |
| 3 | Bhopal | 🇮🇳 India | |
| 4 | Hyderabad | 🇮🇳 India | |
| 5 | Chhatrapati Sambhajinagar | 🇮🇳 India | |
| 6 | Vasai-Virar | 🇮🇳 India | |
| 7 | Nagpur | 🇮🇳 India | |
| 8 | Agra | 🇮🇳 India | |
| 9 | Surat | 🇮🇳 India | |
| 10 | Vadodara | 🇮🇳 India |
With luck
About 10% of wildlife watchers report a River Tern sighting in Vasai-Virar on a given day, based on 131 verified sightings from GBIF citizen-science data. It is the 88th most-seen of the 217 birds we can rate there. Over three days the chance rises to about 30%, and over a week to about 50%, if each day is a fresh chance.
October and November
In those months about 30% of wildlife watchers report a River Tern in Vasai-Virar on a given day, against under 5% in December to July, the lowest months. Those are among Vasai-Virar's driest months, with about 55 mm of rain a month against 840 mm in July.
Between 3 and 6 am
Across all the parks we cover, that three-hour window holds the most River Tern sightings with a recorded time, and about half of them come between 6 am and 6 pm: it is most active around dawn and dusk.
6th of 32
Of the 32 cities where we can rate River Tern sightings, Vasai-Virar ranks 6th at about 10%. The best odds are in Rajkot (India, about 40%), Kota (India, about 20%) and Bhopal (India, about 20%).
GBIF citizen-science records
It is estimated from how often the River Tern is recorded against all the birds logged in Vasai-Virar (131 verified sightings), 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.
