27 Jan 2014

Restoration of a lost seabird community in Mauritius is gaining momentum

White-tailed Tropicbird on Round Island (Photo: J.Cole)
By nairobi.volunteer

The Mauritian offshore islands, especially Round Island and Serpent Island, play an important role in supporting some of the largest breeding colonies of seabirds in the Indian Ocean. However, many seabird populations are facing escalating threats and declines, and moves to protect breeding colonies are becoming increasingly necessary.

The Mauritius Wildlife Foundation (MWF, BirdLife in Mauritius) started a Seabird Translocation Project in 2009, with the aim to restore a lost seabird community on Ile aux Aigrettes and to learn as much as possible in the process. Translocations are a major tool in ensuring the survival of threatened species worldwide. With the project now in its third season, 280 seabirds of five different species have been released and the project is gaining momentum. 

Building on the successes of releases in 2009 and 2011, collections continued in 2013 with an exciting trial translocation from Serpent Island, which took place on 20 March with the assistance of the National Coast Guard (NCG) and the National Parks and Conservation Service (NPCS). Releases of 17 Common Noddies and 21 Sooty Terns ran smoothly with all but a single bird fledging successfully. Harvested nestlings were translocated to a cordoned off area on Ile aux Aigrettes. Unlike previously translocated species these birds were fed twice a day on communal feed trays after the initial weeks of individual hand-feeding, and remained around the release site for some weeks after fledging.

Common Noddy (Photo: J.Cole)

It was not previously thought that these species would be suitable for hand-rearing as they show post-fledging aftercare. However, the birds continued to come back to the island to be fed before gradually spending extended periods out at sea, and the initial releases went very well. This is the first time, as far as is known, that these species have been translocated or hand-reared in any numbers, so any information gained during this trial is of great importance. The mix of different seabird species show diverse behavioural, nesting and feeding requirements, meaning many techniques can be practised and perfected from these trial releases. Information on fledging times, growth and provisioning rates and also fledgling survival will add to the current knowledge on seabirds that is all too often incomplete.

The project has confirmed the number of nestlings of each species that it is possible to hand-rear at any one time with our available facilities. This was tested with the Serpent Island translocations and also with recent helicopter transfers of around 30 tropicbirds from Round Island to Ile aux Aigrettes. Nestlings are harvested at around two to three weeks before fledging and are hand-reared on a diet of fish, squid and octopus. MWF is eagerly awaiting the return of birds released in previous seasons.

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Breakfast time! (Photo: J.Cole)

White-tailed Tropicbirds have been frequently seen flying over the island and Wedge-tailed Shearwaters have been heard calling near release sites. These are all encouraging signs, and MWF hopes to find returning birds on the island over the coming seasons. These translocations demonstrate MWF's long-term commitment to seabird and island restoration and will lay the groundwork for more challenging seabird restoration work in the future, such as the establishment of some rarer seabirds, including the Round Island Petrel and the Red-footed Booby.


Story by Mauritius Wildlife Foundation