Together with Rodrigues (EBA 103), the volcanic Indian Ocean island of Mauritius is an independent nation, and both are part of the so-called Mascarene Islands (see also EBA 101) (see p. 354 for map). On Mauritius, the land rises from low plains in the north and east to a plateau in the south-west which descends steeply to the sea and includes a deeply dissected riverbed, the Black River Gorge. The island was once covered in forest, including palm forest in the northern lowlands (now virtually gone), dry forest elsewhere in the lowlands, and, at higher altitudes, wet evergreen and dwarf forest.

All the extant restricted-range species occur in remaining native evergreen forest, with only Zosterops borbonicus and, to a lesser extent, Terpsiphone bourbonnensis currently living also in entirely exotic vegetation. None of the restricted-range species shows true altitudinal specialization, and although some appear limited to a particular altitudinal range, this is due to factors such as the distribution of predators (R. J. Safford in litt. 1993; detailed information about all the restricted-range birds is given in Cheke 1987c, Jones 1987; see also Jones and Hartley 1995). Three species are shared with neighbouring Réunion (EBA 101), and another restricted-range species which occurs on Mauritius is Meller's Duck Anas melleri, introduced from Madagascar (EBA 096).

The best-known of Mauritius's endemic birds was the (now extinct) Dodo Raphus cucullatus, which became very scarce on the mainland in the 1640s, persisting until c.1662 on offshore islets (Cheke 1987b). A further nine endemic species are known from subfossils (including a night-heron, goose, duck, harrier, two rails, two parrots and an owl), and two more are shared with Réunion (a rail and an owl) (Cowles 1987).

Most of the native vegetation on Mauritius has been cleared and replaced by sugar-cane, tea and conifer plantations. Only remnants of original forest remain (c.5% of the island), mainly in the south-west around the Black River Gorge, but even here it is severely degraded by introduced animals and plants (Safford 1997a). Introduced deer Cervus timorensis, pigs and monkeys Macaca fascicularis cause the most damage, but other exotics affecting forest regeneration are rats (principally black rat Rattus rattus, although brown rat R. norvegicus is also present) and introduced invertebrates (especially the giant African snails Achatina fulica and A. panthera, and many insects) (WWF/IUCN 1994). Cyclones occur regularly and can cause extensive damage, especially to already-degraded habitat (e.g. Jones 1994b).

Not surprisingly, all the endemic birds are threatened as a result of habitat loss and continuing degradation, and also because of nest-predation by introduced rats, monkeys and birds (e.g. Red-whiskered Bulbul Pycnonotus jocosus which affects white-eyes Zosterops in particular). Falco punctatus suffered from organochlorine pesticides in the 1960s, but, following a captive breeding and release programme, made a spectacular recovery from a known population of only six birds to a wild population of 56-68 pairs, with a post-breeding estimate of 229-286 birds in 1994. The population is expected to continue to rise to 500-600 birds (C. G. Jones in litt. 1994).

The status of four species is considered Critical. Columba mayeri was reduced to very low numbers (c.20) with breeding restricted to a single tiny grove of exotic Cryptomeria trees, but a second population from captive-bred birds has been established (aided by supplementary feeding and rat-control and numbering 52 in 1994), and there are plans to extend the release programme, for example to predator-free Ile aux Aigrettes and to a lowland site at Bel Ombre (C. G. Jones in litt. 1994). Psittacula eques, having long since become extinct in the nominate form on Réunion (probably before 1800) but surviving as the race echo on Mauritius, was reduced to 10 or so birds in the 1970s and appeared to suffer almost total breeding failure, but bred successfully subsequently resulting in 16-22 birds in 1993-1994. Zosterops chloronothos was estimated to number some 275 pairs in the mid-1980s, but this figure may have been over-optimistic: intensive fieldwork in the early 1990s indicated only 150 pairs (R. J. Safford in litt. 1994). Foudia rubra has declined from c.250 pairs in 1975 to c.90 pairs in 1990 owing to almost total breeding failure over most of its range, currently being remedied by birds nesting in dense exotic Cryptomeria trees and by a rat-control programme. Fodies unexpectedly disappeared from relatively intact habitat probably because these were 'sink' areas which depended upon adjacent 'source' areas, now destroyed (Safford 1997b; see also Safford 1997c).

The Macchabé/Bel Ombre Nature Reserve (36 km²) has been recognized as the most important key forest (out of 75) for the conservation of threatened birds in tropical Africa (Collar and Stuart 1988), and is now included in the newly created Black River National Park (70 km²). The reserve partly covers the distributions of all the endemic birds, and, although the habitat around Bassin Blanc (especially important for Columba mayeri, Zosterops chloronothos and Foudia rubra: Safford 1991) was not originally included within the boundary of the national park, this area is being bought by compulsory purchase (Jones and Hartley 1995).

Certain offshore island reserves, such as Ile aux Aigrettes (25 ha), show excellent potential for ecological restoration and, where necessary, eradication of introduced predators. These could become key sites for endemic birds (R. J. Safford in litt. 1993; see also Safford and Jones in press).

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Mauritius. Downloaded from https://datazone.birdlife.org/eba/factsheet/115 on 23/11/2024.