Shiny cowbird

The shiny cowbird, belonging to the New World family Icteridae, is predominantly found in South America. It prefers open habitats, including areas impacted by agriculture and deforestation. Since the early 1900s, this bird has gradually expanded its range northward, now reaching the Caribbean islands and southern Florida.

These birds exhibit distinct sexual dimorphism. Males are entirely black with a purplish-blue sheen, while females are a muted brown. They primarily feed on insects and seeds and occasionally forage for grains in cattle troughs.

What distinguishes the shiny cowbird is its unique reproductive strategy. It is an obligate brood parasite, meaning it lays its eggs in the nests of other bird species, such as the rufous-collared sparrow. Host species exhibit varied responses; some raise the cowbird chicks, while others discard the parasitic eggs.

There are seven recognized subspecies of the shiny cowbird, each displaying slight morphological differences. The species has a promiscuous mating system, with males performing courtship displays that include singing and bowing.

Deforestation has compelled the shiny cowbird to extend its range northward, affecting new host species that have not adapted to its parasitic behavior. The shiny cowbird exploits approximately 250 different host species to rear its young. The impact on these hosts varies; some accept the cowbird eggs, while others reject them. The shiny cowbird employs strategies such as pecking at host eggs and hatching earlier than the host's chicks, often resulting in higher mortality rates for the host birds.