In a Flashy Species, Drab Young Males Find Their Own Route to Success With Females

A male Red-backed Fairywren by Joe Welklin via Birdshare.

(Pat Leonard; March 9, 2017)

Just for a moment, think back to those hormone-fueled years of teen angst when personal relationships hijacked rational thought and sparked endless hallway drama. In the competition for female attention, it was usually clear that the the captain of the football team had much better odds than the skinny chess club whiz. And ultimately, the females called the shots.

Male Red-backed Fairywrens feel the same pain.

They’re tiny Australian songbirds (sometimes likened to chickadees of the outback). Males come in two forms: the gorgeous mature males with gleaming red-and-black plumage (the “attractive” ones); and young brown males (the “unattractive” ones) that have yet to acquire their stunning plumage and look pretty much like females.

Past studies have made it clear female fairywrens are more attracted to males with red-black plumage. The red-black males nearly always sire way more offspring than the brown birds. They pair up and raise young with a long-term social mate, but they also court and mate with every willing female they can find (extrapair paternity is the scientific term for this philandering). But the brown males are not completely shut out—they can still pair up with a female and sire offspring.

Scientists studying a population of banded Red-backed Fairywrens near Cairns, Australia, have found that the two types of male employ drastically different strategies for mating success. Their work was published in the January issue of Biology Letters.

“The brown males stay close to home, sing more duets with their mates, guard their mates more, and take good care of their young,” explains lead author Jenélle Dowling, who was a Cornell Lab postdoctoral researcher at the time of the study. “The red-black males spend 98% of their time seeking out other females to mate with, putting on elaborate courtship displays all day long, rarely guarding their mates or taking care of the young.”

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