Conservation
Norway rat (Rattus norvegicus) introduced to the Chatam islands by european explorers.
Conservation status
Extinct. Only one living specimen was ever recorded, collected by Ernst Dieffenbach during his visit to the Chatham Islands in May-June 1840.
Records suggest that the species was already extremely scarce by the late 1830s. Dieffenbach’s specimen was undoubtedly one of the last birds alive (Tennyson & Millener 2006).
Threats
From the abundance of its fossil remains, Dieffenbach’s rRail appears to have survived the combined pressures of human hunting and the presence of Pacific rat (Rattus exulans) for about 400 years following Polynesian colonisation.
However, following European discovery of the islands in 1791, the arrival of sealers and settlers brought increased levels of hunting and the introduction of Norway rat (Rattus norvegicus), cats, pigs and dogs.
The endemic forest rails rapidly succumbed to the onslaught. The first to go extinct was the large Hawkins rail, which may have survived into the early European era and the last was the tiny Hutton’s rail, the last confirmed sighting of which was in 1893 (Tennyson & Martinson 2006).