Pagan Reed-Warbler (Acrocephalus yamashinae)
Posted on 31 December, 1969 in Extinct
Year Last Seen:
1969
Comments:
The species is considered to have become extinct prior to the 1981 volcanic eruption on Pagan, though this event destroyed hopes of the species persisting to the present day. Surveys in the 1970s, 1980s, in 2000 and in 2010 all failed to find any trace of the species, its disappearance primarily a result of severe habitat modification.
Habitat:
It was almost exclusively found in freshwater wetland and wetland edge vegetation (Engbring et al. 1982, Reichel et al. 1992, USFWS 1998).
Causes:
On Pagan virtually all vegetative ground cover was effectively removed at certain periods during the 20th century through a variety of agents including human development, introduced feral ungulates and finally a volcanic eruption in 1981 (Reichel et al. 1992, Hume 2017). However, there had not been any records for some time prior to this, with reports of reed-warblers being present by D. Aldan and J. Sablan into at least the 1960s (Reichel et al. 1992) appearing to be the last observations. The primary threat is thought to have been severe habitat modification through wetland drainage for agriculture and grazing by feral livestock (Hume 2017). Predation by rats and cats is also thought to have driven declines (Hume 2017). The volcanic eruptions in 1981 appear to mark a full stop to the possibility of the species persisting, as all herbaceous and virtually all woody vegetation was destroyed in the last known site, around the upper lake (Reichel et al. 1992).
Distribution:
This species is historically known from Pagan in the Northern Mariana Islands (to USA).