The tracking of Red-Footed Booby on Farquhar Atoll |22 August 2022

Releasing one of the birds with GPS device location

Seabirds such as the Red-Footed Booby (Sulasula) locally known as ‘Fou Bet’, play an important role as indicators of marine hotspots since they join forces with other top-level predators such as tuna when foraging for their prey.

Therefore, understanding their movements at sea by tracking them can help inform the designation of marine protected areas.

This is why the Island Conservation Society (ICS) has teamed up with Université de la Réunion (UR), the Zoological Society of London (ZSL) and the Island Biodiversity and Conservation Centre (IBC/UniSey) to protect their habitat in Seychelles waters and contribute to local and global understanding of the Red-Footed Booby, as part of a Seychelles Conservation and Climate Change Adaptation Trust (SeyCCAT) funded project.

Located on Ile du Sud, Farquhar Atoll (770km southwest of Mahé) are two breeding colonies of Red-Footed Boobies that nest in tidal inlets called the Barachois. It was there that in April this year, the final and most exciting phase of the project took place. Joined by seabird researchers  Professor Matthieu Le Corre, Dr Malcolm Nicoll and Jennifer Appoo (PhD), the Farquhar team, including Jake Letori (conservation officer) and Aurelie Hector (assistant conservation officer), set out to deploy a combination of GPS tracking devices on 54 Red-Footed Boobies.

These small loggers weigh around 18 grammes and were attached to the birds’ tail feathers. Every five minutes, the devices recorded the birds’ location, allowing us to observe where and when they search for fish at sea. Some birds were even fitted with a more advanced tag which acts like a “fit-bit” that humans use, providing information on wing beats, speed, rotation and dive depth, allowing scientists to really delve into their movements and foraging behaviour. 

Each bird was banded with a unique metal ring for identification purposes and after receiving a quick health check that entailed measuring wing length, weight and sex, the birds were released. Handling time was under 10 minutes for each bird and if you are still thinking about how we can tell whether the bird is male or female, you can distinguish this through vocalisations. But, for reassurance and greater accuracy, small breast feathers were taken, giving added information about the genetic connectivity between different booby populations in Seychelles and the western Indian Ocean region. The tracking devices were left on each bird for approximately 4 to 9 days before being retrieved and data downloaded. All tags were successfully recovered and so far, 110 foraging tracks have been identified, with boobies setting out to fish at sunrise and returning to their colony at dusk, spending up to 12.5 hours at sea.

However, a small number of birds went on trips that were up to 3 days in duration, spending the night at sea. The boobies travelled within a radius of 200km around Farquhar Atoll, even travelling outside the Seychelles Exclusive Economic Zone. What was on their menu for them to travel this far? Flying-fish and squid… bon appétit!

Tracking their movements is a relatively small but equally important part of the overall project that complements other aspects of booby research on Farquhar. The team continue to monitor their population numbers through use of standard sampling methods and new technological methods from the sky via drones.

ICS and its partners have finally reached their goal to estimate how many birds are breeding on the atoll, their success of rearing their young and lastly their habitat use of the seas around Farquhar to forage for fish. All of this information will feed into the Seychelles Marine Spatial Plan with the hopeful outcome of protecting healthy and vital parts of Seychelles waters. This is proof that the ‘Fou Bet’ are not so ‘fou’ (and ‘bet’) after all…

Contributed by Jake Letori and Aurelie Hector0

Island Conservation Society (ICS)