This bird reached a length of 13 cm and the wings are 6.3 cm. The length of the tail was 8.6 cm.
The Aldabra Brush Warbler was discovered by British ornithologist Robert Prys-Jones from the Museum of Natural History in London in 1967 and described in 1968 by Constantine Walter Benson and Malcolm Penny on basis of a male, a female and a nest with 3 eggs. Juveniles were never found.
After the discovery the brush warbler left lost until a new survey was made by Prys-Jones from 1974 to 1976. At the end of 1975 he found six further birds which were all males. The birds were ringed and photographed.
Unfortunately in 1983 only one male was left and the Aldrabra Brush Warbler became the rarest and in its occurrence most restricted bird in the world. It was endemic to a 10 ha large coastal strip on the Aldabran island of Malabar. Following intensive surveys, the extinction of this bird was confirmed in 1986. It is listed as officially extinct by the IUCN since 1994.
The possible reasons for its extinction could be attributed to the presence of rats, cats and goats introduced to the atoll many years previously.