Widespread forest loss and the introduction of various species that predate eggs and chicks have had a huge impact on the endemic birds of Mauritius, especially the passerines. The black rat (Rattus rattus) in particular is a major factor in reduced egg and chick survival and control of this introduced predator is a major part of this project.
For both the Mauritius fody and Mauritius olive white-eye management of the populations in the wild has included ‘marooning’ of new sub-populations on the off shore island of Ile aux Aigrettes (IAA).
Intensive efforts to restore IAA have removed most of the invasive mammals and plants, and have established nurseries of endemic trees allowing reintroductions and translocations of native species to the island. IAA is the last remaining example of dry coastal forest which was one common around much of coastal Mauritius. The island has also been developed as an important educational site, showcasing conservation of Mauritian flora and fauna to students and tourists; IAA is the main site of the Learning with Nature programme
There are now well-established populations of Mauritius fody and Mauritius olive white-eye on IAA, and plans are underway to replicate this success on other islands in Mauritius. Ongoing research, supported by the ringing of populations on IAA, has increased knowledge of the ecology and breeding behaviour of these birds which has been applied to the conservation management of other populations.
A key area of current research both on IAA and the mainland is investigating the best methods for rat control and whether rat control by poison increases nesting success. The long-term aim of this research is to be able to create ‘mainland islands’ which are kept at a low enough predator density that endemic passerines are able to successfully breed and fledge young.
In addition to conservation management of the wild populations, we support hand-rearing and captive breeding work at the Gerald Durrell Endemic Wildlife Sanctuary (GDEWS) run by MWF and the National Parks and Conservation Service (NPCS) of the Mauritian government. To date, staff at GDEWS have successfully hand-reared 88 Mauritius fodies, 36 Olive white-eyes (one of the smallest birds to ever be hand-reared) and hundreds of Mauritius kestrels (400), pink pigeons (667) and echo parakeets (150).
In 2015 the Mauritius cuckoo-shrike population was estimated to be 250 individuals, all of which were restricted to just 36 km² of relatively intact native forest in Brise Fer. Ferney Valley, in the Bambous mountain range, has been identified as a potentially suitable translocation site for this species, so eggs are currently rescued from wild nests in Brise Fer and then hand-reared at GDEWS before the fledglings are released in Ferney Valley in an attempt to establish a second wild population.