Western Snowy Plover
The western snowy plover (Charadrius alexandrinus nivosus) is a very small shorebird that forages on invertebrates along beaches, salt marshes, salt ponds and lagoons. Plover nests are usually built in barren or sparsely vegetated areas.
The Pacific Coast snowy plover population ranges along the coasts of Washington, Oregon, California and Mexico, with the largest number of breeding birds occurring south of San Francisco Bay to southern Baja. Because of a decline in active nesting colonies and breeding and wintering birds the Pacific Coast population of snowy plovers was listed as threatened in 1993. At the time the species was listed, approximately 1,500 western snowy plovers nested in the United States.
The decline of Pacific Coast snowy plovers has been attributed to loss of nesting habitat and habitat degradation caused by expanding beach-front development and recreation, human disturbance, encroachment of European beach grass on nesting grounds, and predation.
Western snowy plover. Photo by U.S.G.S.
ENDANGERED SPECIES ACT SUCCESS STORY?
In April 2006 the U.S. Fish and Wildlife Service declared the Pacific Coast western snowy plover an endangered species success story. The population of this once critically imperiled bird has been increasing over the last 15 years and the species will likely recover if Endangered Species Act protections remain in place.
Although the snowy plover still faces the same threats it faced prior to listing, protections have reduced the magnitude of these threats. Since listing, the number of snowy plovers and nesting sites appears to have increased and progress has been made toward bringing the species back to health. Measures taken to benefit plovers since listing include building exclosures to help reduce nest predation, restoring habitat by removing European beachgrass, posting signs and symbolic fencing around breeding sites, distributing information to the public, and increased law enforcement. Currently, the U.S. portion of the Pacific Coast population is estimated to have increased to approximately 2,300 birds.
California : Statewide surveys conducted in the late 1970s estimated the snowy plover population at 1,566 adults and found that only 20 of 53 historic breeding sites were occupied. Later, an additional 11 locations were identified as sites that had once supported, but subsequently lost, nesting plovers. Plover numbers continued to decline, and in 2000 only 976 breeding plovers were observed. Since then, numbers have increased with 1,680 adult plovers observed during 2005 surveys. Ten new low-density breeding sites have been identified, although at least 44 of the historic sites (many of which were once high-density sites) have still not had any recent nesting activity.
Oregon : Historically, snowy plovers nested at 29 coastal locations in Oregon. By the time the species was listed in 1993, 23 of these sites had been lost. Since listing, snowy plovers have reoccupied four of these sites, bringing the number of breeding sites in the state up to ten. Since 1994, the number of adult breeding snowy plovers has been slowly increasing.
Washington : Plovers once nested at five coastal sites, but only three of these sites are currently active. Since listing, habitat conditions have improved at some sites and some additional habitat has been created. The number of breeding snowy plovers in the state has at least remained stable and may have increased since listing.
CENTER ACTIONS FOR THE SNOWY PLOVER
The western snowy plover’s population increases are closely tied to its critical habitat protections. Protected under the Endangered Species Act since 1993, this shorebird’s first measurable steps toward recovery occurred in the late 1990s.
Critical habitat was first designated for the plover in 1999 as a result of a Center lawsuit. A building industry lawsuit to remove the species from the endangered species list was unsuccessful, and the Center intervened in a building industry suit to revise the critical habitat. The revised critical habitat designation in September 2005 protected over 12,000 acres, although this is about 40 percent less acreage than was originally recommended by scientists. The Bush administration gutted protection for thousands of acres that have been determined essential to the survival of the species. The San Francisco Bay area, which has one of the largest populations of snowy plovers anywhere, received no critical habitat protections at all.
In April 2006 the Fish and Wildlife Service proposed an exemption to protections for snowy plovers (link to 4-21-06 FR) that would allow legal incidental “take” — killing, harm, or harassment — of snowy plovers in counties that have met recovery goals for the species (including meeting breeding bird management goals and implementing conservation measures for the plover). This exemption would allow unlimited harm to plovers in some areas without requiring establishment of any breeding pairs, such as in San Francisco and Los Angeles Counties and in San Francisco Bay.
PROTECTING PLOVERS IN CALIFORNIA
San Francisco Bay Area
Human activity and disturbance are the key factors adversely affecting snowy plover coastal breeding sites and breeding populations in California. In August 2005, the Center led a coalition of ten animal welfare, wildlife conservation, child welfare, and park volunteer organizations in filing a formal emergency petition asking the National Park Service to enforce dog-leash laws at the Golden Gate National Recreation Area to protect wintering snowy plovers at Ocean Beach and Crissy Field in San Francisco.
Off-leash groups have demanded that dogs be allowed to roam free throughout the Golden Gate's most sensitive wildlife habitats, despite the fact that park biologists have called off-leash dogs "the most significant recreational threat" to imperiled species such as the western snowy plover. But the recreation area already has the most generous domestic-animal access policy in the country. Because of this, the National Park System's pet management regulations have been supported by responsible animal welfare groups such as the ASPCA, PETA, and the American Humane Association. More than 70 percent of Bay Area residents support the National Park System's pet management regulations.
Although snowy plovers have attempted to breed in the recreation area, all nesting attempts have failed due to human or canine disturbance. Unleashed pets create prolonged and repeated disturbance when they chase birds. Park scientists estimate that snowy plovers are chased by dogs 400 times each winter in the Golden Gate National Recreation Area, and that off-leash dogs are about twice as likely to disturb snowy plovers as leashed dogs. When flushed, snowy plovers must spend vital energy on vigilance and avoidance behaviors at the expense of foraging and resting activity, resulting in decreased energy reserves to complete their annual migration and to successfully breed.
Fortunately, these impacts need not occur. Dogs and imperiled wildlife can coexist at the Golden Gate, but only if the National Park Service’s reasonable leash law is promulgated. Read a press release about the petition.
In 1999 the Center and the Environmental Protection Information Center won a temporary restraining order halting a U.S. Army Corps of Engineers dredging project in Humboldt Bay, after contractors spilled more than 2,000 gallons of oil into the bay on two separate occasions in September and October. The spills polluted more than 40 miles of pristine North Coast beaches and killed thousands of birds, including Western Snowy Plovers.
Plovers and Pesticides
In February 2006 the Center published a report examining the risk pesticides pose to endangered species in the San Francisco Bay Area. Because snowy plovers feed primarily on aquatic and terrestrial insects, the bioaccumulation of environmental contaminants on their nesting and wintering grounds may harm their health and reproduction.