Female hummingbirds avoid harassment by looking as flashy as males


Date:
August 26, 2021
Source:
Cell Press
Summary:
Much like in human society, female hummingbirds have taken it
into their own hands to avoid harassment. By watching white-necked
Jacobin hummingbirds in Panama, researchers discovered that over
a quarter of females have the same brightly colored ornamentation
as males, which helps them avoid aggressive male behaviors during
feeding, such as pecking and body slamming.



FULL STORY ==========================================================================
Much like in human society, female hummingbirds have taken it into
their own hands to avoid harassment. By watching white-necked Jacobin hummingbirds in Panama, researchers discovered that over a quarter of
females have the same brightly colored ornamentation as males, which
helps them avoid aggressive male behaviors during feeding, such as
pecking and body slamming. This paper appears August 26 in the journal
Current Biology.


==========================================================================
"One of the 'aha moments' of this study was when I realized that all
of the juvenile females had showy colors," says first author Jay Falk (@JJinsing), who is now a postdoc at the University of Washington but led
the research as a part of the Cornell Lab of Ornithology and Smithsonian Tropical Research Institute.

"For birds that's really unusual because you usually find that when the
males and females are different the juveniles usually look like the adult females, not the adult males, and that's true almost across the board
for birds. It was unusual to find one where the juveniles looked like
the males. So it was clear something was at play." Male white-necked
Jacobin hummingbirds are known to have bright and flashy colors, with iridescent blue heads, bright white tails, and white bellies.

Female Jacobins, on the other hand, tend to be drabber in comparison,
with a muted green, gray, or black colors that allow them to blend into
their environment. Falk and his team, however, found that around 20%
of adult females have showy colors like males.

As juveniles, all females have the showy colors, but this 20% of females doesn't change to the muted color as they age. It is not clear whether
this phenomenon is genetic, by the choice of the hummingbird, or due
to environmental factors. However, the researchers found that it is
probably the result of the female hummingbirds trying to evade harassment, including detrimental aggression during mating or feeding.

"Hummingbirds are such beloved animals by many people, but there are
still mysteries that we haven't noticed or studied," says Falk. "It's
cool that you don't have to go to an obscure unknown bird to find
interesting and revealing results. You can just look at a bird that
everyone loves to watch in the first place." To learn why some female hummingbirds kept their showy colors, the researchers set up a scenario
with stuffed hummingbirds on feeders and watched as real hummingbirds interacted with them. They found that hummingbirds harassed mainly the
muted colored female hummingbirds, which is in favor of the hypothesis
that the showy colors are caused by social selection. Furthermore, most
females had showy colors during their juvenile period and not during their reproductive period. This means that the only time they had showy colors
is precisely during the period when they're not looking for mates. In combination with other results from the study, this indicates that it
is not sexual selection causing the phenomenon.

In the future studies, Falk and his team hope to use the results of the variation between female white-necked Jacobins to understand how the
variation between males and females in other species may evolve.

========================================================================== Story Source: Materials provided by Cell_Press. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Jay J. Falk, Michael S. Webster, Dustin R. Rubenstein. Male-like
ornamentation in female hummingbirds results from social harassment
rather than sexual selection. Current Biology, 2021; DOI: 10.1016/
j.cub.2021.07.043 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210826111651.htm

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