UW News has posted a story about new insights on a curious fact about white-necked jacobin hummingbirds: 1 in 5 adult females look like males – at least in terms of their plumage.
In a paper published this morning in The Proceedings of the Royal Society B, a team led by Dr. Jay Falk – a postdoctoral researcher in the Department of Biology – reports evidence that females with male-like plumage are engaging in “deceptive mimicry”: They are essentially trying to pass themselves off as males, without acting like them. In the process they receive quite a benefit. As Dr. Falk and his colleagues reported in a paper published last year in Current Biology, females with male-like plumage suffer less aggression from males and can hang out longer at feeders.
Dr. Falk began this research project as a graduate student at Cornell University and continued it as a postdoctoral fellow with co-author Dr. Alejandro Rico-Guevara, a UW assistant professor of biology and curator of ornithology at the Burke Museum.
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.
The study shows that the 1 in 5 adult females with male-like plumage are engaging in “deceptive mimicry”: They are essentially trying to pass themselves off as males, without acting like them. In the process they receive quite a benefit. As Falk and his colleagues reported in a paper published last year in Current Biology, females with male-like plumage suffer less aggression from males compared to females with the more typical muted plumage, and can hang out longer at feeders.
Read the full story in UW News.