Sooty tern project – update and Post by Prof. Chris Feare

I have been to the island 3 times in as many weeks largely due to the need to follow up on preparations for and implementation of the island’s sooty tern project (see my post of 19th May for background information). Professor Chris Feare, the world expert on the species, is in the Seychelles at the moment having come out to oversee the project set-up on Denis. Our two volunteers, Georgia French and Vicki Willits, have also arrived and work is now ongoing.

Following on from our findings last year the models and loud speakers have been set out in the project area. One loud speaker has also been mounted half-way up the trunk of a coconut tree facing out to sea along the prepared entry flight path in order to attract birds that may be flying along the coastline. The southeast monsoon has been late to establish this year and this has a bearing upon the behaviour of Sooty terns – with fewer birds over-flying the island than we would normally expect. The wind has however now set in and we hope that bird numbers will pick up in the next week or two. Despite this, landings have been relatively good with in fact more landings reported in the first week of work this year than throughout the entire season last year! This is very encouraging and underlines I feel, that the lessons learnt regarding the birds’ preferences last year are now reaping benefits in our work. Of particular note was the landing of a pair of birds which then commenced a courting display – exactly what we are hoping for!!!

Chris Feare has kindly written a post (see below) for this blog that sets our work in the broader context of his long term study of Sooty terns in the Seychelles archipelago:

"While Sooty Terns do not command the iconic status bestowed upon some of Seychelles’ rare endemic birds, such as the Seychelles Magpie Robin, Seychelles Warbler and Seychelles Paradise Flycatcher, the Sooty Tern is in fact the Seychelles’ most numerous bird. It breeds in huge spectacular colonies on Bird and Aride Islands, and on the more remote islands of Desnoeufs in the Amirantes, Goelette Island of Farquhar Atoll and Wizard Island of Cosmoledo Atoll. Despite remaining so numerous, Sooty Terns have faced a number of threats since man settled the islands in the mid-eighteenth century. These include the collecting of enormous numbers of their eggs, alteration of the habitats of their nesting islands and the introduction of mammalian predators such as rats and cats. As a result, several former breeding colonies now lie deserted, particularly those on smaller islands close to the main centres of human occupation.
Concern for the species led to their receiving various forms of protection but these are extremely difficult to enforce on remote and often uninhabited islands, and some of the earlier conservation attempts were based on insufficient knowledge of the birds’ biology and behaviour. My own studies of Sooty Terns in Seychelles, now spanning 37 years, along with investigations of colonies elsewhere in tropical oceans, have provided information on their needs and lifestyle that can contribute greatly to their conservation. For example, we know from recent events on Bird Island that restoration of prime habitat, by removing old coconut plantations and encouraging the development of indigenous herb vegetation such as purslane, can lead to a dramatic recovery in numbers. Controlled harvesting of their eggs can also play a part by placing a value on the birds while at the same time regulating the number of eggs that can be taken and the islands upon which harvest is permitted. And eradication of alien predators benefits all indigenous animals, not just Sooty Terns.
Sooty Terns are long-lived birds: on Bird Island ringing studies have revealed several birds 34 years old. In the absence of disturbance, adults usually return to nest on the same island year after year. In an attempt to re-establish a colony on an island known to have supported a large colony 200 years ago, an experiment is currently taking place on Denis Island (see recent blogs). Here, a small area of forest has been cleared and plastic models and broadcasts of Sooty Tern calls are being used, with some success, to attract birds to the island. Once settled, we hope they will continue to return and breed.
Despite our increased knowledge, however, Sooty Terns still hold many mysteries. In particular, we do not know where they feed while they are breeding. Nor do we know where they go when the leave Seychelles after breeding. Ring recoveries in southern India and in northern Australia suggest that they travel far. But we shall not get a better picture of their movements until tiny satellite transmitters, suitable for attachment to Sooty Terns, are available. Only then will we be able to determine whether another of man’s activities, intensive fishing of tuna, presents a threat to these magnificent birds. Sooty Terns do not eat tuna, but they are totally reliant on these predatory fish to drive smaller fish, like sardines, to the ocean surface where they become available to the birds. So if the Sooties prove to feed where tuna are being over-fished, the birds’ populations will be threatened no matter what conservation measures are in place on their nesting islands."