https://www.westerlybirder.com/life-list-1/gray-kingbird
Gray Kingbird | WesterlyBird
gray kingbird
https://digitalcommons.usf.edu/nab/vol57/iss2/1/
"The Vagrancy of Gray Kingbird in North America" by Geroge L. Armisteas and Marshall J. Iliff
By Geroge L. Armisteas and Marshall J. Iliff, Published on 06/01/03