On 25 May Christine and I, along with Wilna Accouche, who replaced Arjan de Groene as General Manager of the Seychelles NGO Green Islands Foundation (GIF), travelled in heavy seas to North Island. On arrival our belongings were taken to the island’s biosecurity centre, where all incoming goods are inspected in a rodent-proof room (to prevent escape rather than entry!) for any unwelcome non-native animals or plants that might have tried to hitch a ride. Cats and rats were eradicated from the island in 2003 and 2005 respectively and every attempt is made to guard against the return of these or arrival of other potentially dangerous alien species.
On the island we were immediately struck by the absence of bird calls, most of which had previously emanated from vociferous Common Mynas. Readers of my blogs will be aware that GIF has been administering a myna eradication programme on the island, funded by the island and led by WildWings Bird Management. This is aimed at protecting native birds, especially the endemic Seychelles White-eye, from predation of eggs, chicks and possibly adults, at which mynas have proved to be adept with other small Seychelles endemics. During our visit we neither saw or heard any mynas, indicating that the eradication programme, which has involved trapping and shooting, has progressed well.
However, two new volunteers, Sarah Atkinson and Claire Waters (daughter of Jeremy Waters, who previously spent almost a year on the island as a myna project volunteer) are tasked with monitoring the distribution and behaviour of any remaining mynas in preparation for a final attempt to remove the remaining birds. It is proving very hard for them to estimate the numbers remaining as on their frequent surveys they can never be sure whether birds that they see or hear are new birds for that particular survey, or whether they are birds that they have already counted but which have moved to a new part of the census route. And there is also the chance that during a survey they could miss some birds that move between sites. Their guestimate is that at least seven mynas still live on the island but accept that this could be an underestimate. Nevertheless, the huge reduction in numbers is readily apparent and very encouraging.
The current silence could be a bit misleading, however, as adult mynas are currently moulting their feathers. When they lose wing and tail feathers their flight is somewhat impaired and during moult many birds keep a low profile, remaining quieter than at other times of year and also moving less. The moult will finish in late July-August and at this time we expect location of mynas and their removal to be more easily achieved.
Successful eradication of mynas will have to be followed by continuing vigilance for arrivals from other islands, notably Silhouette, only seven kilometres away. But once eradication has been confirmed, there will hopefully be opportunities for North Island to receive other Seychelles endemic birds. Studies are already under way to determine whether food availability is sufficient to support populations of other species of endemic. If food supplies are adequate, North Island could join the list of islands that have been rehabilitated to the extent that more threatened species can be given a new safe home, providing long-term benefits to Seychelles’ biodiversity.