Acrocephalus luscinius (Quoy & Gaimard)

Nightingale Reed Warbler (Acrocephalus luscinius)  

The Nightingale Reed Warbler was an endemic species of Guam, where it was called Ga’kaliso, or Ga’karriso in Chamorro, the language of the native inhabitants.  The species reached a size of about 17 cm.  

The Nightingale Reed Warbler inhabited dense reed thickets in freshwater- and brackish marshlands, which, during the 20th century, were largely drained. Hence the reasons for the extinction of this species lie mainly in the extensive destruction of its habitat. The unintentional introduction of the Brown Tree Snake (Boiga irregularis (Merrem)), which has led to the extinction of nearly all of Guam’s native bird species, plays a minor role here.  

The last individuals were seen in the year 1969.  


The island of Alamagan in the north of the Mariana Archipelago is still harboring a smaller population of reed warblers (about 300 birds), which hitherto have been assigned without any reservation to this species (resp. formerly subspecies), which, however, in a biogeographical sense must be considered completely impossible (hereto see map).  The birds from the island of Alamagan are either most closely related to the species from Alamagan’s neighbor island, Pagan, the Pagan Nightingale Reed Warbler (Acrocephalus yamashinaeTakatsukasa), or even represent a distinct species.  


The reed warbler populations of all other islands in the Mariana island chain were until recently treated as subspecies of this species, but are now considered as distinct species.  



[1] H. Douglas Pratt, Phillip L. Bruner, Delwyn G. Berrett: A Field Guide to the Birds of Hawaii and the Tropical Pacific. Princeton University Press 1987 
[2] James D. Reichel; Gary J. Wiles; Phil O. Glass: Island extinctions: the case of the endangered Nightingale Reed-Warbler. Wilson Bull. 104(1): 44-54. 1992 
[3] David Pearson; Peter Kennerly: Reed and Bush Warblers. Christopher Helm 2009 [4] Alice Cibois; Jon S. Beadell; Gary R. Graves; Eric Pasquet; Beth Slikas; Sarah A. Sonsthagen; Jean-Claude Thibault; Robert C. Fleischer: Charting the course of reed-warblers across the Pacific islands. Journal of Biogeography 38(10): 1963-1975. 2011


reed warbler species of the Marianas known from specimens

Depiction: Alexander Lang


edited: 17.10.2020