Puffins that stay close to their partner during migration have more chicks

(Dr Annette Fayet, University of Oxford; 7 April 2017)

Puffin pairs that follow similar migration routes breed more successfully the following season, a new Oxford University study has found.

Many long-lived birds, such as swans, albatrosses or indeed, puffins, are known for their long-lived monogamous, ‘soulmate’ pairings. Scientists have long understood that in these species, reproductive performance is influenced by pair bond strength and longevity, with long-established pairs usually better at rearing offspring. However, in species like puffins which have to migrate to distant wintering grounds during the non-breeding season, very little is known about how mates maintain their pair-bond and behave. Do they keep in contact to maintain their relationship? Or do they go their own way and abandon their mate until the following spring?

The new study which features in the April 7th 2017 edition of Marine Ecology Progress Series, focused on whether puffin pairs stayed in contact during the winter months or instead headed off and migrated independently, prioritising their individual health and wellbeing, and whether this had any effect on the pairs’ subsequent breeding success.

Over the course of six years, the team from Oxford’s Department of Zoology, in collaboration with the London Institute of Zoology, used miniature tracking devices called geolocators to track the migratory movements and behaviour of 12 pairs of Atlantic Puffins, breeding on Skomer Island, Pembrokeshire. They assessed if and how much pairs’ migratory strategies were related to their future breeding performance and fitness.

While pair members migrated separately, their routes were notably similar during the first part of the winter. Partners would then follow separate paths at the later end of the season, but synchronised their timings of return to the colony in spring.

A key finding of the study is that pairs which followed more similar migration routes bred earlier and more successfully the following spring, showing that there is a clear benefit for puffins to migrate close to their mates. This proximity may make it easier for pairs to synchronise their return to the colony in spring.

The findings also reveal that while migrating close to its partner is key to a puffin’s reproductive success, there are other factors at play. Female puffins were found to forage more than males, proving critical to their breeding success the following season. Female puffins that foraged more over winter were able to lay eggs earlier and rear pufflings more successfully, most likely because they were in a better pre-breeding condition.

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