Molothrus ater (brown-headed cowbird) is a small blackbird with a short, conical bill and long, pointed wings (Roof 1997). Males appear black with a unique brown head and neck. Females are either dullish grey or brown throughout. The bill is a dull grey and the eyes are black.
Molothrus ater (brown-headed cowbird) breeding begins in April, peaks in May, starts declining in June, and occurs sporadically through July (GMNH 2000). The brown-headed cowbird is parasitic and therefore builds no nest. The female can lay approximately 40 eggs in one breeding season, usually 1-2 in each host's nest. The eggs usually hatch after 10-13 days, and the young fledge in 10-13 days, with the host adults successfully raising at least one hatchling.
Molothrus ater (brown-headed cowbird) prefer open habitats of low or scattered trees interspersed with grasslands; they usually avoid unbroken forest. Brown-headed cowbirds prefer, and may require, areas of short grass or bare ground for foraging. They are commonly associated with cattle pastures and feedlots (GMNH, 2000). Other habitats are open coniferous and deciduous woodlands, forest edges, brushy thickets, agricultural land and suburban areas (Rothstein 1994, in Sullivan, 1995).
Molothrus ater (brown-headed cowbird) often feed on the ground, away from vegetation (Roof 1997). Their main food items are seeds and arthropods. They sometimes hawk, looking for slow flying insects. In a quantitative analysis of the brown-headed cowbird's diet, it was found that nearly 75% was 'weed' seed, with most of the remaining 25% made up of grasshoppers and beetles
Compiler: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
Review: Dr. Keith Arnold. Professor. Department of Wildlife and Fisheries Sciences, Texas A and M University, USA
Publication date: 2005-01-24
Recommended citation: Global Invasive Species Database (2022) Species profile: Molothrus ater. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=310 on 09-12-2022.