Circus spilonotus
Silhouette: Shyamal · PhyloPic
In 3 days ~10% in a week ~20%
The eastern marsh harrier (Circus spilonotus) is a bird of prey belonging to the marsh harrier group of harriers. It was previously considered to be conspecific with the western marsh harrier (Circus aeruginosus) but is now usually classified as a separate species.
It is 48 to 58 cm long with a wingspan of 113 to 137 cm; like most birds of prey, the female is usually larger than the male. The male's plumage is variable; typically the head, breast, back and wing-coverts are blackish with pale streaks. The rest of the wing is grey with black wingtips and a white front edge. The tail is grey, the rump is white and the underparts are mostly white. The female is dark brown with buff streaking on the head and underparts. The rump is often whitish and the tail has dark bars. Young birds are dark brown with buff on the head and a pale patch on the underwing.
It is usually silent but has a mewing call which is most often uttered at roost sites. Eastern marsh harriers are generally migratory apart from the Papuan... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Manas National Park | 🇮🇳 India | |
| 2 | Way Kambas National Park | 🇮🇩 Indonesia | |
| 3 | Cuc Phuong National Park | 🇻🇳 Vietnam | |
| 4 | Kaziranga National Park | 🇮🇳 India | |
| 5 | Cat Tien National Park | 🇻🇳 Vietnam |
Rare
Under 5% of wildlife watchers report an Eastern Marsh-Harrier sighting in Manas National Park on a given day, based on 55 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 230th most-seen of the 377 birds we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
April and December–February
In those months about 10% of wildlife watchers report an Eastern Marsh-Harrier in Manas National Park on a given day, against under 5% in March and May–November, the lowest months. Those are among Manas National Park's driest months, with about 90 mm of rain a month against 1070 mm in June.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Eastern Marsh-Harrier sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 5 parks where we can rate Eastern Marsh-Harrier sightings, Manas National Park has the highest daily chance: under 5%. Next come Way Kambas National Park (Indonesia, under 5%) and Cuc Phuong National Park (Vietnam, under 5%).
Same genus: Circus
The closest relatives of the Eastern Marsh-Harrier that you can see in Manas National Park (genus Circus, Harriers) are Pied Harrier (about 10%) and Hen Harrier (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Eastern Marsh-Harrier is recorded against all the birds logged in Manas National Park (55 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.
