Outer Islands Birdwatching Expedition

The Outer Islands Birdwatching Expedition is the Seychelles' only publicly bookable offshore pelagic birding product — an annual voyage run by Silhouette Cruises Ltd (operating as Aldabra Expeditions) that ventures from Victoria, Mahé across 1,500 kilometres of the western Indian Ocean to reach Aldabra Atoll, one of the largest raised coral atolls in the world and a UNESCO World Heritage Site. The expedition's centrepiece is a series of dedicated offshore chumming sessions over the Seychelles Bank, directly replicating the technique pioneered in December 2014 by ornithologist Hadoram Shirihai and Seychelles-based birder Adrian Skerrett — the first time chumming had ever been attempted in these waters. On that original two-day session, frozen blocks of fish offal lowered into the water over the Seychelles Bank drew in 13 Matsudaira's Storm-Petrels, 25 Wilson's Storm-Petrels, and 1 Black-bellied Storm-Petrel, opening what the Seychelles News Agency described as entirely new eco-tourism potential in the Indian Ocean.

Matsudaira's Storm-Petrel (Hydrobates matsudairae) is the expedition's signature offshore target. It is a large, long-winged North Pacific storm-petrel that disperses deep into the Indian Ocean from its breeding colonies on the Volcano Islands of Japan, and the Seychelles Bank is one of the very few places on Earth where it can be encountered reliably from a boat. Satellite tracking of Indian Ocean tubenoses has also confirmed that Barau's Petrel and Mascarene Petrel — both Critically Endangered endemics of Réunion Island — cross Seychelles waters during the May expedition window, making the offshore sessions a globally important opportunity to record these poorly known species at sea. White-faced Storm-Petrel dances low above the wave surface during transits between islands; Wilson's Storm-Petrel is regular throughout. Wedge-tailed Shearwater and Tropical Shearwater accompany the vessel through the outer island groups, while Red-footed Booby and Greater Frigatebird are near-constant companions from Aride southward.

The expedition is not a pure pelagic cruise but combines the offshore chumming sessions with visits to the most ecologically significant seabird colonies and endemic land-bird habitats in the Seychelles. Day two brings Aride Island, a Scientific Reserve managed by the Island Conservation Society: Aride holds more breeding seabird species than all other granitic Seychelles islands combined, including the world's largest colonies of Lesser Noddy and Tropical Shearwater, plus Abbott's Booby, White-tailed Tropicbird, and Red-tailed Tropicbird. The transit from Mahé to Aride is already productive, with frigatebirds and tropicbirds following the vessel. The Amirantes Group on days three and four introduces the outer coral island birds: Red-footed Booby in the Indo-Pacific white morph, Sooty Tern, Brown Noddy, and Bridled Tern are all encountered here. Cosmoledo Atoll in the Aldabra Group is the largest colony of Greater Frigatebird in the Indian Ocean; Brown Booby and Masked Booby nest here too. Aldabra itself provides the only accessible colony of Abbott's Booby outside of Christmas Island, along with flamingoes, White-throated Rail, Aldabra Drongo, and the world's largest population of Aldabra Giant Tortoise.

Twelve Seychelles endemic land-bird species appear across the granitic island stops: Seychelles Kestrel, Seychelles Blue Pigeon, Seychelles Bulbul, Seychelles Warbler (Cousin and Cousine), Seychelles Magpie-robin (Frégate, Cousin), Seychelles Scops-Owl, Seychelles Paradise Flycatcher (La Digue), Seychelles Fody, Seychelles Sunbird, Wright's Skink, and Seychelles Sheath-tailed Bat are all possible depending on island stops.

The voyage is conducted aboard SY Sea Bird (a comfortable sailing yacht) or MV Maya's Dugong (a purpose-fitted expedition motor vessel with seven en-suite twin cabins for up to 14 guests). Chumming is conducted by lowering large frozen blocks of fish offal into the water during a drift, a technique now established in Seychelles waters since the 2014 pioneering session. The expedition runs annually in May and is bookable directly through Silhouette Cruises Ltd at [email protected] or via the aldabraexpeditions.com website; pricing is quoted on application. Nature Travel Birding (naturetravelbirding.com) also organises departure groups on this vessel with Hadoram Shirihai as lead guide.