Giant Cowbird vs Shiny Cowbird: How to Tell Them Apart

Giant Cowbird

Molothrus oryzivorus

Medium182 gForest

The male giant cowbird is 34 cm (13 in) long, weighs 174–242 g (6.1–8.5 oz) and is iridescent black, with a long tail, long bill, small head, and a neck ruff which is expanded in display. The female is smaller, averaging 29 cm (11 in) in length and weighing 144–167 g (5.1–5.9 oz). The female is less iridescent than the male, and the absence of the neck ruff makes her look less small-headed. Juvenile males are similar to the adult male, but browner, and with a pale, not black, bill.

ID text from Wikipedia, CC BY-SA 4.0

Recorded by Niels Krabbe · Call · Pichincha: Tandayapa ridge 3 km SSW Tandayapa, Ecuador · CC BY-SA 4.0

Photo: gailhampshire from Cradley, Malvern, U.K · CC BY 2.0

Shiny Cowbird

Molothrus bonariensis

Small41 gWoodland

The physical appearance of the shiny cowbird adult depends on the subspecies. Sizes range from 31–40 grams (1.1–1.4 oz) in mass and 18 cm (7.1 in) in length (M. b. minimus), to 55–65 grams (1.9–2.3 oz) in mass and 22 cm (8.7 in) in length (M. b. cabanisii). Basic adult plumage for M. b. bonariensis is black with purple-blue iridescence for males, and dusty gray-brown for females. M. b. cabanisii males have plumage similar to M. b. bonariensis, while females are paler in colouration. M. b. aequatorialis males have violet iridescence and females are dark in colour. M. b.

ID text from Wikipedia, CC BY-SA 4.0

Recorded by Gabriele Magurno · Song · Ezeiza, Ezeiza Partido, Buenos Aires Province, Argentina · CC BY-SA 4.0

Photo: Daniel Talevi · Public domain

Where you might meet both

Colombia Brazil Costa Rica Ecuador Peru Panama Trinidad & Tobago Bolivia Venezuela Argentina Guyana Mexico French Guiana Suriname Paraguay

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Photos and recordings are credited to their authors under the licence shown. Full profiles: Giant Cowbird and Shiny Cowbird.