Oklahoma's black vulture (Coragyps atratus) breeding range expands north to Washington county

Abstract

A Black Vulture nest with two eggs was discovered in Washington County, Oklahoma in April 2015, and is the northernmost known nest in Oklahoma. Staggered initiation of incubation, a difference in egg size, or a discrepancy in food allocation may have contributed to size and developmental rate differences between the chicks. Population trend data suggest an ongoing increase in Black Vulture numbers, and an increase in observations at and beyond the currently published northwestern edge of the breeding range suggest that a range expansion may also be underway.