This week I have returned to Reunion Island in the Mascarene archipelago (Western Indian Ocean) for a regional conference on landscape rat control to save birds at imminent risk of extinction. I haven’t been back to Reunion since I left nearly five years ago after working for a year on island conservation in the Mozambique Channel, but the conservation advances on Reunion since then have been amazing, made by a large group of co-operating agencies but particularly involving my friends at the Society for the Study of Reunion Ornithology (SEOR). I’m undertaking field trips with them in particular relation to two bird species I wanted to share news about.
The tuit-tuit is the local Creole name for the Reunion cuckoo-shrike. It currently numbers at less than 50 pairs in one forest patch on Reunion so is one of the rarest birds in the world, but its situation has improved greatly over the last 5 years so that the population is now increasing. Although by far not out of the danger zone yet, the tuit-tuit’s change in fortune has come about because of a commitment to control invasive rats to zero-density across the entire forest habitat where the species breeds – over 600 hectares. This is done with a grid of bait stations set every 25-30 metres. After controlling rats the breeding success of the tuit-tuit increases from less than 35% to 100%. This week, however, as we were out in the field, a fire was also encroaching on the forest reserve and threatening the birds. Ironically, rat invasion is a catastrophe just like a fire and both are solved by flying helicopters around in the sky with buckets attached beneath them.
The other species at risk of extinction is not faring so well. The Mascarene black petrel, or ‘timize’ in Creole (a type of supernatural name for its haunting call but never seen) exists in unknown numbers at an unknown high altitude location on Reunion. Occasionally, a bird crash lands attracted to urban lights, a major threat for the two species of petrel on Reunion. It is estimated that perhaps less than a few hundred birds remain, but without having found their breeding location, likely on an inaccessible cliff, it is impossible to implement conservation measures to save this species, let alone estimate how many remain. The greatest threat to the Mascarene petrel and its cousin the Barau’s petrel which also nests exclusively on Reunion Island is predation by introduced rats and cats. Population models I helped construct in 2008 show that without pest control seabird species such as these will rapidly go extinct. This week I hope to participate in another field mission to try and locate the breeding colony as the birds once again commence their summer breeding season, for a species where every chick fledged counts.