Wednesday, December 27, 2006


Speaking of seabirds, there is good news from Wake Island, an atoll in the North Pacific, located approximately two-thirds of the way from Hawaii to the Northern Mariana Islands. The US annexed Wake Island in 1899 in order to create a cable station; an air and naval base was constructed there in 1940-41, and the island was captured by the Japanese early in WWII. After the war, Wake was developed as a stopover and refueling site for military and commercial aircraft transiting the Pacific, with the island's airstrip being used since 1974 by US military and commercial cargo planes, as well as for emergency landings. Seabirds there have suffered through the years, especially as a result of the presence of feral cats.

A collaboration between the Department of Defense, The Endangered Species Recovery Council, Wildlife Management International of New Zealand, and Marine Endeavors was initiated in mid-2003. As a result cooperators began a concerted effort to remove feral cats that have been causing significant damage to indigenous bird populations on the atoll. By the start of this year, about 170 cats had been removed from the three islets comprising the atoll. Searches in July and August failed to find any signs of cats; however, it will require several years without sightings to confirm that no cats remain.

With the removal of feral cats, Pacific Rats have increased. Rodenticide has been placed in populated areas, but current rodent control effort has been less effective than originally hoped for. Local Hermit Crabs often reach the bait before the rats, but fortunately the bait is not toxic to them. Currently both the contractor and Air Force are investigating alternative rat eradication options.

The benefits to seabirds have been immediately evident. Booby populations were among the first to increase after cat control was initiated. Breeding pairs of Masked Boobies went from 3 in 1996 to 20 by 2004, while Brown Boobies increased from 73 pairs in 1996 to 162 in 2003. Wedge-tailed Shearwaters expanded to form at least three colonies. By August 2004, Gray-backed Terns, a species not recorded breeding on the atoll since the 1980s, were raising young in two new colonies. Some of these birds are thought to be immigrants from Johnston Atoll and French Frigate Shoals, Hawaii.

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