Extinction of Birds on Guam


Guam is a 541 square kilometer island in the western South Pacific, equidistant from Japan to the north, the Philippines to the west, and New Guinea to the south. In the 1960s wildlife authorities noticed that birds were entirely absent from the southern one-third of the island; by the 1970s birds were missing from two-thirds of the island; and by 1985 most birds were in isolated pockets at the northern tip of the island, or completely gone. The accidentally introduced brown tree snake, Boiga irregularis, was responsible not only for the extinction of the birds but also the decimation of the island’s lizards, mammals, and small domestic animals. By October 1996 only three of Guam’s twelve native forest bird species still survived in the wild, and most forests of Guam are empty of bird life. Two of the three native bat species have also vanished in the last few years.

Thomas Fritts is a research biologist and chief of the Biological Survey Program with the U.S. Geological Survey. A lifelong student of reptiles, he received a Ph.D. from the University of Kansas with a specialty in tropical herpetology. In a recent paper in BioScience he explained the effects of the brown tree snake on the wildlife of Guam. We spoke with Dr. Fritts about how the brown tree snake arrived on Guam and its effects on the wildlife there.

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