Endangered Species in the Pacific Islands
Guam Broadbill / Myiagra freycineti
||The Guam broadbill, also known as "Chuguangguang" in the native language, was a small bird that had a bluish head and neck with a metallic luster; a back and upper wing coverts that were near green-blue; a rump that was grayer than the back; white chin and throat feathers; light cinnamon breast feathers; bluish-slate tail; black bill and feet; and dark brown iris.
|Guam broadbill - Photo credit Anne Maben/Guam DAWR
Habitat & Behavior:
The Guam broadbill was endemic to Guam in the Mariana Archipelago. This insectivorous species was once found in all habitats of the island with the exception of southern savannas but is now extinct.
Like other flycatchers in Micronesia, pairs aggressively defended territories against other birds, and approached and scolded human intruders as well. The species foraged within the forest, and individuals were rarely seen outside protective vegetation. The call was a loud series of whistles which were given fairly commonly during morning hours.
Past & Present:
Although the species was probably never abundant, reduction in Guam broadbill range was noted from 1950 into the early 1980s. Prior to 1950, the species occupied 310 miles of habitat throughout the island of Guam. By 1950, broadbill range had been reduced to 193 miles or 62% of its former range. By the early 1970s, the species was entirely absent from the southern two-thirds of the island but still widespread and common northern Guam into the mid-1970s. Known estimates of 460 birds in 1981 and fewer than 100 individuals in 1983 from the Pajon Basin had dwindled to only one sighting of a male in October 1983. In 1983, the population declined 83% in the Ritidian Basin area and was further restricted to the extreme northern end of Guam in the Pajon Basin.
Reduction in Guam Broadbill range and its eventual extinction has been attributed to excessive pesticide spraying during and after World War II, the spread of avian diseases, and predation by introduced animals, such as the rat, the monitor lizard, and the brown treesnake (Boiga irregularis).
In 1983, a male broadbill was collected for captive propagation but this effort failed as other wild individuals were not located and the captive male died of unknown causes. By the mid-1980s, the population continued to decline dramatically from undetermined causes. Studies conducted by the U.S. Fish and Wildlife Service's Patuxtent Wildlife Research Center in 1983 indicated that pesticide overuse and avian diseases were not responsible for broadbill declines in the early 1980s. Instead, studies implicated predation by the brown treesnake as the single most important factor in the decline of Guam's native forest birds, including the Guam broadbill.
The Guam broadbill has not been seen since May 15, 1984, and was listed as an endangered species on August 27, 1984. The Service removed the Guam broadbill from the Federal List of Endangered and Threatened Wildlife in 2004.