Molothrus oryzivorus
Silhouette: Andy Wilson · PhyloPic
In 3 days ~70% in a week ~90%
The giant cowbird (Molothrus oryzivorus) is a large passerine bird in the New World family Icteridae. It breeds from southern Mexico south to northern Argentina, and on Trinidad and Tobago. It may have relatively recently colonised the latter island. It is a brood parasite and lays its eggs in the nests of other birds.
The giant cowbird was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the orioles in the genus Oriolus and coined the binomial name Oriolus oryzivorus. Gmelin based his account on the "rice bird" from Cayenne that had been described in 1782 by the English ornithologist John Latham in his multi-volume work A General Synopsis of Birds. The specific epithet is from Latin oryza meaning "rice" and -vorus meaning "eating". The giant cowbird is now one of six cowbirds placed in the genus Molothrus that was introduced in 1832 by William Swainson.
Two subspecies are recognised: Wikipedia →
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Santa Cruz de la Sierra | 🇧🇴 Bolivia | |
| 2 | Belém | 🇧🇷 Brazil | |
| 3 | Guayaquil | 🇪🇨 Ecuador | |
| 4 | Barranquilla | 🇨🇴 Colombia | |
| 5 | San Pedro Sula | 🇭🇳 Honduras | |
| 6 | Medellín | 🇨🇴 Colombia | |
| 7 | San José | 🇨🇷 Costa Rica | |
| 8 | Caracas | 🇻🇪 Venezuela | |
| 9 | Panama City | 🇵🇦 Panama | |
| 10 | Bogota | 🇨🇴 Colombia |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Parque das Aves | 🇧🇷 Brazil |
Possible
About 30% of wildlife watchers report a Giant Cowbird sighting in Main Ridge Forest Reserve on a given day, based on 287 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 39th most-seen of the 103 birds we can rate there. Over three days the chance rises to about 70%, and over a week to about 90%, if each day is a fresh chance.
February to April
In those months about 50% of wildlife watchers report a Giant Cowbird in Main Ridge Forest Reserve on a given day, against about 10% in October, the lowest month. Those are among Main Ridge Forest Reserve's driest months, with about 65 mm of rain a month against 230 mm in October.
Between 7 and 10 am
Across all the parks we cover, that three-hour window holds the most Giant Cowbird sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 50 parks where we can rate Giant Cowbird sightings, Main Ridge Forest Reserve ranks 2nd at about 30%, level with the leaders once rounded. The best odds are in Amboró National Park (Bolivia, about 30%).
GBIF citizen-science records
It is estimated from how often the Giant Cowbird is recorded against all the birds logged in Main Ridge Forest Reserve (287 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.
