The Red-eyed Vireo is a woodland songbird that searches leaves in the canopy for caterpillars and also eats fruit in its South American wintering areas.
It is olive green above and white below, with a clear gray, black, and white head pattern. Its iris becomes red by the end of its first winter.
In 2020 and 2021, researchers tagged 85 adult male Red-eyed Vireos at a breeding site in northwestern Pennsylvania. They timed departures for 22 birds; 19 (86%) left within two hours after sunset. These 22 departures ranged from August 26 to October 8, and 16 fell between August 30 and September 11. Departure times ranged from 15 minutes before sunset to about four hours after it, averaging 73 minutes after sunset.
Post-departure detections were obtained for 46 tagged birds. Among the 15 vireos with timed departures and migration detections, movements headed south toward Florida; one bird stopped for 11 days at a fall stopover 41 km southeast of the breeding site. Departure was more likely on nights with rising surface pressure and high humidity. Some birds also left in headwinds.
An extinction-risk assessment has not been added yet.
Among the 22 vireos with confidently timed departures, 16 left between August 30 and September 11. Departure dates across the full set of recorded birds extended from August 26 through October 8, showing that the start of fall migration varied among individuals.