BROWN-HEADED COWBIRD (Molothrus ater) – (See images below)
DESCRIPTION: The Brown-headed Cowbird male has a brown head with the rest of the plumage being black. The conical bill, the eyes, the legs and feet are also black. Females are brown overall, and the bill, eyes, legs and feet are black. This bird measures around 20 cm (8 inches) long.
NAME: This bird’s English name ‘Cowbird’ relates to its diet, as it follows cattle to pick on ground insects disturbed the those large animals. The Latin genus name ‘Molothrus’ derives from Greek ‘molobros’, a parasite person. As for the Latin species name ‘ater’, it means ‘black’, for the male plumage color.
HABITAT: Open areas such as forest edges, fields, shrubland and populated areas.
DIET: Insects, particularly those that have been disturbed in the ground by grazing animals, also seeds and grain.
Parasitic behavior: The brown-headed cowbird is an obligate parasite species. It is known to lay its eggs into the nest of more than 200 other bird species, including birds that are larger. When hatching the young will be fed by the host parents, often to the detriment of the parents’ own hatchlings.
Host response: Various responses have been observed in host species to this parasitic behavior, such as ejection of the cowbird egg, building a nest layer on top of it and laying new eggs, leaving the nest, or rejecting the ‘alien’ hatchling outright.
‘Mafia’ behavior: Not only do cowbirds lay their eggs in other species nests, but they apparently also check on their eggs in the host species nests. If their eggs have been removed, they will ransack the host species nests, forcing them to build a new one. They then lay their egg in that new nest of the host species.
DISTRIBUTION: This bird is a North American species. The breeding range of this bird covers roughly the southern half of Canada and the western half of the USA. It is a year-round resident in Nova-Scotia, the remainder of the USA and the middle region of the northern half of Mexico. Wintering grounds include southern Florida, Baja California and the remainder of Mexico.
ON PEI: The brown-headed cowbird breeds on Prince Edward Island and is a year-round resident.
CONSERVATION: The numbers of this bird would range above 100 million, and the species is widespread. It is not considered at risk.
SIMILAR SPECIES: Common Grackle, Red-winged Blackbird
REFERENCES: (Maritimes Breeding Bird Atlas) (Missouri Department of Conservation)

Brown-headed Cowbird, male – Kensington, PEI – Apr. 27, 2017 – Heather Harris
Brown-headed cowbird male, Heather Harris
Brown-headed cowbird female, NC
by Dick Daniels
Savannah Sparrow nest with own egg and Brown-headed Cowbird egg – Oil field in Alberta – June 2013 – photo by Kati Fleming
Savannah sparrow nest with own egg and
Brown-headed cowbird egg, Kati Fleming
Common Yellowthroat feeding Brown-headed Cowbird juvenile – July 2018 – photo by Agathman
Common yellowthroat feeding Brown-
headed cowbird young, by Agathman

In this video below there’s a female brown-headed cowbird opening up black sunflower seeds in its ‘granivorous’ bill, swallowing the ‘kernel’ and spitting out the seed envelope.