Further Evidence of Breeding by Shiny Cowbirds in North America

Abstract

We report evidence of egg-laying in northern Florida by the Shiny Cowbird (Molothrus bonariensis). Examination of the ovary and oviduct of a female trapped in Alachua County, Florida in late June 2006 revealed ovulation and recent passing of eggs. Two other Shiny Cowbird females captured in late May and early June had convoluted oviducts but showed no other signs of recent egg-laying. These three specimens add to the few female Shiny Cowbirds captured in North America. Our observations represent further evidence that Shiny Cowbirds likely breed in North America and additional evidence of breeding outside of southern Florida.