Pacific Southwest Region
California, Nevada and Klamath Basin

Service Determines Van Rossem’s Gull-Billed Tern Does Not Warrant Protection

Sep 20, 2011

For Immediate Release: 
September 20, 2011

Contact: Jane Hendron, Carlsbad Fish and Wildlife Office - 760/431-9440 ext. 205

Service Determines Van Rossem’s Gull-Billed Tern Does Not Warrant Protection
Under The Endangered Species Act

CARSLBAD, Calif. -- The U.S. Fish and Wildlife Service (Service) announced today it has completed a status review of van Rossem’s gull-billed tern (Gelochelidon nilotica vanrossemi) and concluded it does not warrant protection under the Endangered Species Act (Act). The Service made this finding after a thorough review was conducted involving the best available scientific and commercial information regarding the status of and threats to the species. 

The status review was undertaken after the Service determined that a petition to list van Rossem’s gulled-billed tern throughout its range as endangered or threatened under the Act provided substantial information indicating listing may be warranted. The petition was submitted to the Service June 3, 2009, by the Center for Biological Diversity.

Petitioners cited several reasons why the Service should list van Rossem’s gull-billed tern including: loss or degradation of nesting and foraging habitat, and decline in species range; overutilization for commercial or subsistence purposes (egg and young hunting); predation; inadequacy of regulatory mechanisms; and other natural or manmade factors (climate change, contaminants).

Based on a thorough review of information and data available, the Service has determined that the magnitude, imminence, and intensity of threats do not indicate van Rossem’s gull-billed tern is in danger of extinction or likely to become endangered within the foreseeable future throughout all or a significant portion its range.

Van Rossem’s gull-billed tern has a current breeding range from extreme southern California to the Mexican state of Guerrero and potentially farther south. In the United States, the subspecies is known to nest at only two locations – the Salton Sea and southern San Diego Bay. The wintering range of the subspecies includes coastal western Mexico and possibly western Central America.

The best available information indicates the current breeding range of van Rossem’s gull-billed tern has increased from its known historical breeding range. Moreover, they are opportunistic and adaptive nesters able to move to new nest sites and renest within the same year, even if the sites are not available every year.

Unlike most tern species, which eat only fish, van Rossem’s gull-billed tern forages over a wide range of habitat consisting of both wetland and upland areas, which include estuaries, river margins, aquacultural impoundments, as well as open scrub, pasturelands and irrigated agricultural fields and associated canals. They are resourceful foragers and feed on a variety of available small prey items, including crabs, lizards, insects, chicks of other bird species, and fish.

Although foraging and nesting has been lost in the past within the gull-billed terns’ range, the subspecies is not highly susceptible to nesting habitat loss and appears to be resilient to changes to its habitat. Additionally, evidence does not indicate the capture or collection of eggs or chicks of van Rossem’s gull-billed terns are a threat or will become a threat throughout its known distribution at this time. Similarly, disease and contaminants do not appear to be a significant threat despite their presence in the environment where the subspecies nests and forages.

While sea-level rise resulting from climate change is generally predicted to impact coastal-nesting waterbirds like van Rossem’s gull-billed tern, available information fails to provide evidence supporting climate change is a significant threat to this subspecies. This is because their nest sites at coastal locations are often dynamic, plus two nesting locations are inland, and several others are protected by a network of man-made levees used as salt evaporation ponds.

The Service anticipates current conservation and management efforts within the United States and Mexico will continue and we will continue to actively engage the public and others in the search for improved and innovative ways to conserve and protect species and their habitats.

Van Rossem’s gull-billed tern is a medium-sized migratory seabird that can live up to 10 to 20 years or more. It has a heavy black bill and pale, pearly gray upper parts, wings, and tail, with white underparts, and wing linings. During breeding season, the bird develops a black cap extending from the region between eye and bill, including the eyes, to the nape.

A copy of the 12-month finding can be viewed online today at the Federal Register Public Inspection Page. The official copy will be published on September 21, 2011, and will be posted on at Docket No. FWS-R8-ES-2010-0035. New information, materials, comments, or questions concerning this finding can be submitted to or to the Carlsbad Fish and Wildlife Office, 6010 Hidden Valley Road, Suite 101, Carlsbad, CA 92011. A photo of the tern may be viewed on Flickr.

- FWS -

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