In the annual quest for the best breeding mate, the older female Nazca booby’s choice to pair with a younger mate may contribute to lifespan differences within the species, said Emily Tompkins, the lead researcher who co-authored “Sex-specific patterns of senescence in Nazca boobies linked to mating system” with biology professor David J. Anderson.
The study is the latest in decades-long research by Anderson, who studies several seabird species. He and his students have been banding Nazca boobies born on Española Island, a roughly 37-square-mile Galápagos Island outpost, for more than 30 years.
The females, which are about 16 percent larger than the males, control mating and decide when it’s time to “divorce” a current partner for one with a better chance at successful breeding. An excess of adult males in the Nazca booby population has led to this practice of “serial monogamy.” When the males enter their late teens, their chance of breeding plummets, while females continue to breed nearly every year. So, the older females of the species often choose a younger mate each breeding season. And that seems to have led to a shorter lifespan for females, Tompkins said. MORE
Header image: Nazca boobies at the Punta Cevallos colony in the Galápagos Islands. Credit: J. Howard.