We are now coming to the end of seabird nesting season in the Seychelles, so first an update on how the season went. Since you last heard from us, we have finally got round to crunching the numbers from our annual seabird census, carried out in July; this year we had an estimated total of 55,000 breeding pairs of lesser noddys, 1,986 pairs of brown noddys, 1,011 pairs of white-tailed tropicbirds and 812 pairs of fairy/white terns.
Our lesser noddy (Anous tenuirostris) nest monitoring continued throughout the months of August and September and is drawing to a close for this year. A total of 154 nests were monitored over a period of 3 and half months. Overall, breeding success is estimated at between 78-89%. Most of our chicks are still dependant on their parents for food, but are otherwise all grown up and are regularly taking to the skies. They can be seen gathering on Cousine’s sandy beach in large numbers to test out their flying skills.
Our sooty tern (Onychoprion fuscatus) numbers were a bit lower this year compared with last year, but the colony is still producing chicks and this year’s cohort are now proudly sporting their juvenile plumage, having lost their hedgehog-like fluffy down and grown their impressive black feathers and forked tails. Many have already fledged from the colony site, and there are plenty of adults and juveniles filling the sky above the island. A flush count conducted in July while the adults were still sitting on their eggs produced an estimate of 80-125 nests in total, and of these, 76 chicks were ringed with unique metal ID rings once they’d reached the appropriate age in August. Despite these lower numbers, this season we also have a major success story to report!
As well as the established colony in the south of the island, attempts have been made for the past few years to attract birds to another equally suitable site in the North. At this north site, the vegetation has been managed to replicate that of the existing colony; following this, decoy birds and a solar-powered caller are installed. We are excited to say that our first successful sooty tern chick has fledged from the site!
Whilst the noddy and sooty tern fledglings are finding their wings, the breeding season for the bridled terns (Onychoprion anaethetus), and tropical and wedgetailed shearwaters (Puffinus bailloni and Puffinus pacificus) is only just getting started. All three species are now sitting on eggs, the shearwaters in their burrows on the hill sides and the bridled terns in amongst the rock crevices along the south ridge.
Things are never quiet here on Cousine – as many of our seasonal seabirds now start to leave the island for the first time, the Hawksbill sea turtles (Eretmochelys imbricata) will start to arrive to lay their eggs on our beach. Surprisingly there hasn’t been any emergences yet, but elsewhere in the Inner Islands the nesting has already begun. This year, some changes have been made to the sea turtle programme; construction of a hatchery, designed to protect some of our nests from crab predation, is underway. We’ll update you on that next time around!
Original content source: Cousine Island
Original authors: James McClelland and Becky Hodgkiss
Original image source: Cousine Island