Pacific Islands Fish and Wildlife Office
Pacific Region

Endangered Species in the Pacific Islands

Guam Bridled White-Eye / Zosterops conspicillatus / Nosa

Painting of Guam bridled white-eye The Guam bridled white-eye measured about four inches long; had a green upper part and yellow and white lower part. It had a white orbital ring around its eye after which the bird is named. The bridled white-eye had wing and tail feathers that were dark brown with greenish-yellow edges. The females tended to be lighter in color than the males. The Guam subspecies was the largest of the other white-eyes found in the Mariana Islands, and had a gray crown and very prominent "spectacles."
Guam bridled white-eye - Painting by Doug Pratt

Habitat & Behavior:
The bridled white-eye was found in most available habitats on Guam including mature, pristine limestone forest, scrubby second-growth, grasslands and foot hills of southern and central Guam, beach strand, wetlands of Hagatna swamp, and mixed woodlands and second-growth of the northern plateau.

These birds formed small flocks of three to six birds that moved and foraged actively in the upper canopy. The white-eye was nonterritorial even when nesting, and had a low volume contact call which is voiced frequently, particularly when groups are moving from tree to tree. It appeared to nest year-round, laying two to three eggs per clutch. It fed primarily on insects, apparently taking little fruit or nectar.

Past & Present:
The Guam subspecies was endemic to Guam. The distribution of the Guam subspecies was formerly island-wide. By 1945 there were still a few white-eyes in southern Guam. White-eyes were last recorded in central Guam in 1961.

A U.S. Fish and Wildlife Service survey in 1981 estimated that 2,220 white-eyes remained, but they occupied only 2% of their known historical range in northern Guam and none of their former range in central and southern Guam. The last observation of this bird was in June 1983 in the Pajon Basin, and this subspecies is now considered extinct. The primary factor in their extinction was the introduced brown treesnake (Boiga irregularis).

Conservation Efforts:
The U.S. Fish and Wildlife Service began conducting systematic forest bird surveys in Micronesia in 1981. The majority of forest birds were protected on Guam by the turn of the century with such acts as Guam Public Law 6-87, which prohibited the taking, buying or selling of wild birds or their eggs and the Endangered Species Act of Guam (Guam Public Law 15-36), which protects both locally and federally listed endangered species on Guam. The Government of Guam has established four conservation reserves that provide protected habitat for many native species. However, the brown treesnake is still abundant and widespread on Guam, therefore; attempts to reintroduce white-eyes on Guam cannot be undertaken.


Last updated: September 20, 2012
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