Molothrus bonariensis
Silhouette: Andy Wilson · PhyloPic
In 3 days ~10% in a week ~30%
The shiny cowbird (Molothrus bonariensis) is a passerine bird in the New World family Icteridae. It breeds in most of South America except for dense forests and areas of high altitude such as mountains. Since 1900 the shiny cowbird's range has shifted northward, and it was recorded in the Caribbean islands as well as the United States, where it is found breeding in southern Florida. It is a bird associated with open habitats, including disturbed land from agriculture and deforestation.
Adults are sexually dimorphic. Males are all black with a purple-blue iridescence. The female is smaller, with dull brown plumage that is sometimes paler on the underparts. Females of the species can be distinguished from the female brown-headed cowbird by their longer, finer bills and flatter heads. The shiny cowbird's diet consists mainly of insects, other arthropods and seeds, and they have been recorded foraging for grains in cattle troughs.
Like most other cowbirds, it is an obligate brood parasite, laying its eggs in the nests of many other bird species such as the rufous-collared sparrow. Different host species show different responses to their nests being parasitised, with behaviours ranging from accepting and caring for the cowbird eggs, to rejecting the eggs from the nest. As the shiny cowbird is an effective generalist brood parasite, it can be considered the South American counterpart to the brown-headed cowbird. Wikipedia →
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Montevideo | 🇺🇾 Uruguay | |
| 2 | Mendoza | 🇦🇷 Argentina | |
| 3 | Santiago | 🇨🇱 Chile | |
| 4 | Asuncion | 🇵🇾 Paraguay | |
| 5 | Buenos Aires | 🇦🇷 Argentina | |
| 6 | Bogota | 🇨🇴 Colombia | |
| 7 | Curitiba | 🇧🇷 Brazil | |
| 8 | Cordoba | 🇦🇷 Argentina | |
| 9 | Brasilia | 🇧🇷 Brazil | |
| 10 | Rosario | 🇦🇷 Argentina |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Bioparque Wakatá | 🇨🇴 Colombia |
Rare
Under 5% of wildlife watchers report a Shiny Cowbird sighting in Everglades National Park on a given day, based on 406 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 132nd most-seen of the 273 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.
April and June–July
In those months about 20% of wildlife watchers report a Shiny Cowbird in Everglades National Park on a given day, against under 5% in September to March, the lowest months.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Shiny 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.
31st of 60
Of the 60 parks where we can rate Shiny Cowbird sightings, Everglades National Park ranks 31st at under 5%. The best odds are in Iberá National Park (Argentina, about 40%), Chapada dos Guimarães National Park (Brazil, about 30%) and El Palmar National Park (Argentina, about 30%). All parks ranked.
GBIF citizen-science records
It is estimated from how often the Shiny Cowbird is recorded against all the birds logged in Everglades National Park (406 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.
