Researchers analyzed more than half a million records of banded birds in North America over 27 years. Credit: Tyler Moulton/Unsplash
Birds have a lot to do in their short lives: defend territories, build nests, raise chicks and feed themselves. But the toll of these activities may be greater for female birds than for male birds. A new study by UCLA ornithologists has found that female birds have lower survival rates than males. The research is the first to study female bird survival in a large dataset and shows that the phenomenon is more widespread than previously recognized. In mammals, females generally have higher survival rates, and why birds, which are not mammals, show the inverse is a puzzle the researchers are trying to solve.
"Female birds, in general, are understudied relative to males, so that's what I wanted to research," UCLA doctoral candidate in ecology and evolutionary biology Joanna Wu said. "As I began reading papers on female birds, I was surprised to notice a pattern that the survival rate seemed to be lower in females than males. I expected that males would have lower survival because they're usually the ones competing for mates and so forth. So these previous findings concerned me, since females are crucial to reproduction and the continuation of populations over time."
