Gull-Billed Tern|Faces Downturn

     WASHINGTON (CN) – The U.S Fish and Wildlife Service has determined that a full status review of the van Rossems gull-billed tern is warranted, after completing a 90-day review of a petition by the Center for Biological Diversity to protect the species.

     The 90-day review is the first step in the Endangered Species Act listing process, and leads to a 12-month examination of the status of the species. The public may submit data on the history, taxonomy, life cycle and habitat of the tern, and information on threats to the species across its range.
     The van Rossem’s gull-billed tern, a medium-sized seabird, is one of two subspecies of gull-billed tern in North America. A migratory species, the tern nests along the Pacific coast of Mexico including the Gulf of California in the spring and summer. An additional coastal nest colony is in California’s San Diego. The birds also nest inland around northeastern Baja California, Mexico, and at the Salton Sea, Imperial County, California. The Salton Sea and San Diego Bay are the only nesting areas for the subspecies in the United States.
     According to the agency, the extent of the tern’s winter range is not known but likely includes the Pacific coast of Mexico, Central America, and possibly northwestern South America.
     The Center for Biological Divirsity says in its petition that van Rossem’s gull-billed tern is threatened by loss of foraging habitat in the San Diego Bay area, which extends to areas used by the U.S. military for training and recreation.
     The petition also claims that tern nesting and foraging habitat at the Salton Sea is threatened by declining water levels caused by diversion irrigation from the Colorado River, and what water is available is being transferred from the Imperial Valley agricultural areas to the San Diego region for municipal use. This causes nesting islands in the Salton Sea to become part of the mainland, allowing predators easy access to the nesting site.

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