Puffins who migrate together have more chicks together

Puffin pairs who follow similar migration patterns tend to birth more chicks than those who follow disparate flight plans, according to new research.

A number of studies have highlighted the importance of mate bonding for reproductive efficiency. But scientists weren't sure how the stress of long-distance migration affects pair-bonds.

Researchers at Oxford University and the London Institute of Zoology used geolocators to track the movements of 12 pairs of Atlantic puffins.

Their findings -- detailed in the journal Marine Ecology Progress Series -- showed mates don't share identical flight patterns, but follow similar paths during the beginning and end of their winter migration. This proximity was important for reproductive success. Pairs who followed similar paths birthed more chicks after returning to their mating grounds in the spring.

Scientists found other factors were more important than migratory patterns to reproductive success. Females who spent more time searching for food during winter months birthed more healthy chicks.

"While migrating close to one's partner leads to more successful breeding in puffins, female winter foraging effort seems to be even more critical to ensure high reproductive success," Annette Fayet, a junior research fellow at Queen's College, said in a news release. "A likely explanation for this finding is that female puffins which spend more time fueling up over winter return to the colony in better condition and are able to lay higher quality eggs, rearing stronger chicks."

Still, little is known about puffins' time at sea. Researchers hope followup studies -- buoyed by smaller, more accurate tracking devices -- will further illuminate the details of the species' wintertime behavior.

"At the end of the breeding season puffins disappear at sea for over eight months before returning the following spring, and scientists have long had questions about where they go during that time," Fayet said. "However, until recently tracking devices were too big to use on small birds like puffins. The recent miniaturization of tracking technology means we can now study the at-sea movements of puffins and other small migratory seabirds remotely over months and even years."