They may glide around and look cute and sociable, but the world of hummingbirds is filled with aggression. Now it seems that some female hummingbirds have evolved to avoid this – by adopting the bright plumage of their male counterparts.
U.S. researchers caught more than 400 white-necked Jacobin hummingbirds in Panama.
Surprisingly, they found that more than a quarter of the females wore similar flashy plumage – iridescent blue heads, bright white tails and white bellies – to the males. Typically, female Jacobins tend to be duller in comparison and burn with muted shades of green, gray, or black that allow them to blend into the environment.
Experiments conducted by the researchers suggested that the flashy male-like clothing helped the females avoid aggressive male behavior during feeding, such as chopping and slapping with the body.
When the researchers examined the captured birds, they found that all the young or young Jacobins showed flashy shades. In general, across most bird species, young birds typically resemble the corresponding sexes of the adult birds.
“So it was clear that something was at stake,” said the study’s first author, Jay Falk, who is now a postdoctoral fellow at the University of Washington but led the research as part of the Cornell Lab of Ornithology and the Smithsonian Tropical Research Institute.
“Every woman and he starts looking like the grown men. As they get older, about 20% of the females retain that plumage, and then 80% switch into the sad plumage. ”
It is generally believed that ornamental, showy plumage in many species has evolved as a function of competition for mate. But in this case, most females did not retain the colorful plumage as they were sexually mature and were looking for mates, which was a hint that so-called sexual selection was not the cause, he noted.
Falk and his colleagues tried to answer why some female Jacobins continued to look like males as adults by leaving stuffed hummingbirds on feeders (male-like females, sad females and males) and looked at how true hummingbirds interacted with them in different places in Panama .
They found that most of the sexual behavior of what appeared to be true male hummingbirds was directed at the stuffed boring females, reinforcing the idea that sexual selection was not the right explanation, according to the study. published in the journal Current Biology.
However, when looking at aggressions between the stuffed and true hummingbirds, the researchers found that stuffed, sad females were often attacked more than the stuffed showy females. “So that kind of gave us an indication that it has something to do with social selection and competition for food rather than competition for peers,” Falk said.
In general, people thought of hummingbirds as tiny little fairies drinking nectar from flowers, he added. “But they are constantly fighting with each other … aggression is a big part of their lives.”