I stroll across the road on a rainy day to look for the Cape May Warbler that appears annually in the churchyard bottle-brush (Callistemon) trees only to find a life-bird in the trees on the back fence. A cause for celebration you would think. But no. This species is the Shiny Cowbird (Molothrus bonariensis), found throughout South America wherever there is deforestation and now rapidly expanding from Panama to the west and north through Costa Rica and up to the United States.
It appeared in my area at Guayabo National Monument just a few kilometers away in early January of this year and I now find three individuals here in San Antonio. Even worse, the glossy purple male was in courtship display to the two dull brown females. Since these are brood parasites they won’t nest but will instead supplant native Costa Rican species, mostly small songbirds. Although the purple sheen of the male is aesthetically pleasing, Richard Garrigues’ photo below is of a not-so-charming streaky immature.