Sterna acuticauda
Silhouette: Sharon Wegner-Larsen · PhyloPic
In 3 days ~10% in a week ~30%
The black-bellied tern (Sterna acuticauda) is a tern found near large rivers in the Indian subcontinent, its range extending from Pakistan, Nepal and India to Myanmar. It has become very scarce in the eastern part of its range and the International Union for Conservation of Nature has assessed its conservation status as being endangered.
They have a black belly in the summer and a deep forked tail. They can sometimes resemble whiskered terns (Chlidonias hybrida), but the deeper fork of the tail and the black on the lower belly distinguish them from the shallow fork and black closer to the breast on the whiskered tern. Considering that sequence analysis supports moving the similar black-fronted tern ("Sterna" albostriata) into Chlidonias, this species might also be better placed in that genus, but no research has yet been conducted.
The black-bellied tern grows to a length of 32 to 35 cm (13 to 14 in). In the breeding plumage, the crown and nape are black and the upper parts are pale grey. The throat is white and the breast pale grey, gradually darkening to a black belly. The wings are long, slender and pointed and the tail is deeply forked with sharply pointed tips... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Satpura National Park | 🇮🇳 India | |
| 2 | Ranthambore National Park | 🇮🇳 India |
Rare
Under 5% of wildlife watchers report a Black-bellied Tern sighting in Satpura National Park on a given day, based on 50 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 154th most-seen of the 259 birds we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
December
In that month about 20% of wildlife watchers report a Black-bellied Tern in Satpura National Park on a given day, against under 5% in February to October, the lowest months. That is one of Satpura National Park's driest months, with about 10 mm of rain against 690 mm in July.
Yes
Of the 2 parks where we can rate Black-bellied Tern sightings, Satpura National Park has the highest daily chance: under 5%. Next come Ranthambore National Park (India, under 5%).
GBIF citizen-science records
It is estimated from how often the Black-bellied Tern is recorded against all the birds logged in Satpura National Park (50 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.
