Introduction

The Yellow-headed Blackbird, although most numerous in prairie wetlands, is a conspicuous breeding bird in deep-water, emergent wetlands throughout nonforested regions of western North America. Its generic and specific name, Xanthocephalus, means “yellow head,” a tribute to the male’s striking plumage. Highly social, these large-bodied blackbirds are polygynous, nesting on grouped territories. Postbreeding birds eat mostly grains, often forming large flocks that forage in uplands and roost in wetlands. Flocks migrate to the southern United States and Mexico for the winter.

The first detailed description of this species was by Prince Charles Lucien Bonaparte (1825), although Thomas Say (Swenk 1933) and Sir John Richardson (1831) apparently collected the species in 1820. Its current scientific name was first used by Jordan (1884). George Ammann (1938) and R. W. Fautin (1941a, b) provided early detailed accounts of breeding Yellow-headed Blackbirds. Subsequent studies by Willson (1966), Orians (1980, 1985), and others have expanded our knowledge of the breeding biology of this species. Detailed behavioral accounts have been produced by Nero (1963) and Orians and Christman (1968). We have made extensive use of these studies, and readers are referred to them for more detail and discussion.