River Martin - Status

Status

The White-eyed River Martin was seen in Thailand in 1972, 1977 and 1980, but not definitely since. There are unconfirmed sightings from Thailand in 1986 and Cambodia in 2004. It is classified as critically endangered by the International Union for the Conservation of Nature and Natural Resources (IUCN). This designation means that a species' numbers have decreased, or will decrease, by 80% within three generations. This species may be extinct, but the IUCN will not categorise it as such until extensive targeted surveys have been conducted. Despite legal protection under Appendix 1 of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) agreement, it was captured by locals along with other swallows for sale as food or for release by devout Buddhists. Following its discovery by ornithogists, trappers were reported to have caught as many as 120 and sold them to the director of the Nakhon Sawan Fisheries Station who was unable to keep them alive in captivity. The small population may therefore have become non-viable.

One factor that reduces the chances of re-discovering the White-eyed Martin is the drastic decline in the numbers of swallows wintering at Bueng Boraphet, its only known site, from the hundreds of thousands reported around 1970 to maximum counts of 8,000 made in the winter of 1980–1981. It is not certain whether this represents a real decline or a shift in site in response to persecution. Other potential causes for the species' decline include the disturbance of riverine sand bars, the construction of dams which flood the area upstream and alter the downstream hydrology, deforestation, and increasing conversion of its habitat to agriculture. Very few swallows now roost in the Bueng Boraphet reedbeds, preferring sugarcane plantations, and, despite searching, the White-eyed River Martin has not been found in other nearby large swallow roosts. Bueng Boraphet has been declared a Non-Hunting Area in an effort to protect the species, but surveys to find this martin have been unsuccessful. Past surveys include several at Bueng Boraphet, a 1969 survey of the Nan Yom and Wang Rivers of northern Thailand, and a 1996 survey of rivers in northern Laos. A possible unverified sighting was reported in 2004.

The total population size of the African River Martin is unknown. In the late 1980s, it appeared to be common, if local, and large numbers were seen on migration in Gabon. However, it is particularly poorly known in the Democratic Republic of the Congo (DRC), and it is unclear if there is any relationship between the birds breeding in the DRC and those breeding in coastal areas of Gabon and the Republic of Congo. A flock of 15,000 birds was seen in 1997, and a mixed flock with Rosy Bee-eater Merops malimbicus was estimated at 100,000 birds; nevertheless, due to the lack of detailed information, the species is classed by the IUCN as Data Deficient. In the 1950s, the species was caught and eaten in large quantities in the DRC by the local population, and this practice could be increasing. Breeding colonies in river sandbars are also liable to flooding, but thousands of birds were breeding on the grasslands east of Gamba as recently as 2005.