Project to re-establish a breeding colony of Sooty terns on Denis island

When Denis Island was discovered in 1773 it hosted large seabird populations including a colony of Sooty Terns (Sterna fuscata). In the following years the birds left, due to various reasons mainly habitat change. To re- establish a colony an area of a former coconut plantation was cleared as the Sooty Tern is a ground nesting species that requires open grassland. Since the Sooty Tern re-colonization project initiation in 2008, preparation of the site prior to the breeding season has always preoccupied keen environmental enthusiasts on Denis Island. This includes the removal of encroaching plants and trees, the cutting of grass to a suitable height and placing the Sooty models and loud speakers. This project is unique, based on the knowledge and under the supervision of Prof. Chris Feare. The dummy birds and the playing of the Sooty colony noise through the speakers shall encourage the birds to nest on the prepared site.

Monitoring commences every year around May with the arrival of the birds. This year we had a few weeks delay mainly in obtaining the needed broadcasting equipment. By late June the set-up design at the South Point were completed. Within the weeks a few birds were seen circling/flying over the breeding site. Visual observations were mainly opportunistic partly due to lack of staff and other work.

Similar to last year, unfortunately it seems this year is also an odd year with regards to Sooty Terns nesting, presumably related with abnormal weather patterns and consequences for fish stock and seabird activity. On Bird Island, Prof. Chris Feare, reported that breeding activity got off to an early start but tailing off early with no new birds coming in. Incubation shifts are a bit longer than normal suggesting that food might not be as available as normal. The laying season normally ends mid-July but after an early start it might end early this year.

Sooty Terns  formerly nested on several islands in the Seychelles group but on most islands, especially the smaller ones, colonies became extinct as a result of excessive egg and adult harvesting by people, introduction of exotic predators, and habitat change. Commercial harvesting of eggs continues on some islands and forest development in one of the larger colonies, on Aride Island, is now limiting the numbers that can nest there. Provision of alternative nesting areas on which they may breed may thus play an important part in maintenance of sooty tern populations in Seychelles. On Denis Island we are attempting to re-establish a sooty tern colony through habitat management, decoy birds and playback of recorded sooty tern calls.