The Effects of the Brown Treesnake on Guam

The BTS is responsible for the extinction or local extirpation of four birds on Guam: the Guam Flycatcher, Rufus Fantail, Bridled White-Eye and Micronesian Honeyeater.  The BTS preys on the endangered Mariana Fruit Bat of which less than 300 are left in the wild, and three of the 12 native lizards on Guam have become extinct due to the BTS. 

A Mariana Fruit Bat, of which less than 300 are left in the wild. Image taken from: http://www.guamdawr.org/learningcenter/
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Current recovery efforts are in place concerning the animal species on Guam that have been decimated by BTS.  These species include: the Guam Rail, the Mariana Crow, the Guam Micronesian Kingfisher, the Island Swiftlet and the Mariana Fruit Bat.

The BTS affects agriculture by preying on agricultural animals and may increase the vulnerability of agricultural crops to insect pests, and the risk of insectborne diseases affecting humans and other animals due to the loss of avian/reptilian insectivores.

The Guam Rail, a flightless native bird of Guam, disappeared from southern Guam in the 1970s and was extirpated from Guam in the 1980s. This species is now bred in captivity and is being reintroduced in Guam in a 22-ha area protected from Brown Treesnakes by perimeter barriers and traps.

The BTS also causes major power outages: 1600 have occurred in the 20 year period from 1978-1997.  In the year 2002 alone, there were 200 power outages caused by BTS.  Considering this, if a BTS were to cause an electrical outage that encompassed the entire island of Guam, $3 million in lost productivity would occur.

One of the most major concerns, however, is the spread of the Brown Treesnake from Guam to other Pacific Islands and the U.S. mainland areas.

The Mariana Crow is a native forest bird of Guam. Its eggs are threatened by predation from Brown Treesnakes.

The reproduction of BTS is poorly understood.  The BTS females usually lay four to 12 oblong eggs in a clutch.

The BTS is slightly venomous, producing venom through two larger fangs on the back of the upper jaw.  Its venom is not considered dangerous to adult humans, but can be for small children.  The venom is used to subdue and kill small prey on which the BTS normally feeds.