Female mammals usually outlive males, but a 27-year study found the pattern was reversed among...

A 27-year study by UCLA researchers found adult female birds had a 12.4% lower survival rate than adult males across 35 North American bird species.

The study, published in Proceedings of the Royal Society B, analyzed over 563,000 bird-banding records from 1992 to 2018.

On average, female birds lived for 1.36 years after adulthood, while males lived for 1.61 years.

Lead author Joanna Wu said females are often studied less, and the findings were surprising because males usually compete for mates.

The research used data from the Institute for Bird Populations, which monitors birds across the United States and Canada.