Sooty Terns – the next generations?

Sooty Tern with a ring - the mainstay of our early studies (Chris Feare)
Sooty Tern with a ring – the mainstay of our early studies (Chris Feare)

Sooty Terns are long-lived; many of the birds we ringed on Bird Island in 1972-3 lived for more than 30 years. Young birds take a long time to mature, the vast majority not returning to breed until they are 5-6 years old. About 91 percent of breeding adults survive from one year to the next but only about 26 percent of chicks that leave the island survive to return to breed when they are old enough. These pieces of information are vital if we are to understand how Sooty Tern populations respond to the effects that we humans are imposing on them, through climate change, commercial fisheries, habitat changes and direct exploitation. With such a long-lived bird with a slow rate of reproduction, however, it has taken many years to obtain the information on which these estimates are based.

The changes that we are inflicting may take place over several years and so continued monitoring is essential to understanding what is affecting them, how, and to what extent. Modern miniature technology is now allowing us to investigate facets of their life that I could only dream of ten years ago. We have now discovered where Bird Island’s Sooty Terns go when they leave the island in September/October until the following March/April through the use of tiny devices called geolocators. This year Christine Larose and I are investigating where breeding adults feed during the incubation and early chick-rearing periods by tracking their movements using tiny GPS tags. In future, many other possibilities for study will become available, but who will do the work? I began studying Bird Island’s Sooty Terns 44 years ago and have been able to pursue this research since then thanks to the generosity and support of the owners, Guy Savy, his late wife Marie France and now their sons Alex and Nic. I have also been able to make periodic visits to other Seychelles colonies (and to colonies elsewhere in the world), and have built up a picture of their basic biology in Seychelles.

Dylan counting eggs in a 10 square metre circle in the Bird Island colony
Dylan counting eggs in a 10 square metre circle in the Bird Island colony (Chris Feare)

The hope now is that others will follow and I hope we can enthuse and train people who might be able to continue these studies in future. Christine and I have played a small part in this process while on Bird Island. Eleven-year-old Dylan Savy son of Nic and Jo and grandson of Guy, has been helping us, looking for ringed birds, catching them and recording their numbers; watching us put GPS tags on some of the birds; and helping us to prepare for our monitoring of chick survival for 2016 in September. He is now a Sooty Tern enthusiast par excellence, happy to be pecked and hit on the head while contributing to our work.

Aurelie receiving instruction from Christine and me on fitting a GPS tag (Richard Jeanne)
Aurelie receiving instruction from Christine and me on fitting a GPS tag (Richard Jeanne)

We have also been visited by Aurelie Duhec and Richard Jeanne, who have been monitoring the Sooty Tern colony on Goelettes Island, Farquhar Atoll. This was before the atoll was hit by cyclone Fantala in April and their workplace was to a large extent destroyed. They will eventually return there, hopefully to deploy GPS tags on their Sooty Terns, having watched all stages of the process while with us.

Good luck to these youngsters. We hope their Bird Island experiences will pave the way to further work on our beloved Sooty Terns.

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