White-necked jacobin hummingbirds sport a colorful blue-and-white plumage as juveniles. When they grow into adulthood, males retain this dazzling pattern, while females develop a more “muted” palette of green and white — at least, most females. Curiously, about 20% of females defy the norm and retain male-like plumage into adulthood.
“Why do some female jacobins look like males? It’s a mystery made up of multiple pieces,” said Jay Falk, a postdoctoral researcher at the University of Washington. “Is there a benefit? Is there a cost? Is it just appearance, or do these females also act like males?”
Now those pieces are falling into place. In research published Sept. 7 in the Proceedings of the Royal Society B, Falk and co-authors at the UW, Cornell University and Columbia University report that adult female white-necked jacobins with male-like plumage are mimicking male appearance — but not male behavior. In addition, their strength and body size are similar not to males, but to fellow females with muted plumage.
Read more at University of Washington
Photo Credit: Kathy & sam via Wikimedia Commons
