Conserving Borderline Species: A Partnership between the United States and Canada
Birds
Whooping Crane (Grus americana)
Status
Canada (COSEWIC): Endangered
U.S. (USFWS): Endangered; Experimental populations (Colorado, Florida, Idaho, New Mexico, Utah, and Wyoming)
Photo Brian Johns
Description
Standing 1.5 meters (5 feet) tall, the whooping crane is the tallest bird in North America. Boasting a snowy white body and thin black legs, it has a long, pointed beak, a long neck, and a white and black head with a red crown. It has immense, black-tipped wings that allow it to glide with little effort and stay aloft for up to 10 hours at a time.
Ecology
Whooping cranes migrate north from their wintering grounds in March and April. They breed in the boreal wetlands of Canada's Wood Buffalo National Park. The nest is usually a flat-topped mound of vegetation in shallow water. The female lays one clutch per year which usually consists of two eggs, but most often only one chick will fledge. Both adults incubate the eggs and raise the young. Whooping cranes feed on crustaceans, fish, small mammals, insects, roots, berries, and grain. They begin migrating south in early September.
Causes of Decline
Historically, the whooping crane ranged from an area near the Arctic Circle south to central Mexico and from Utah east to the Atlantic coast. Having once numbered at least 10,000 birds, by the late 1800s the total global population had decreased to an estimated 1,500 individuals and continued to decrease. The decline was due to hunting, egg collection, and habitat disturbances such as conversion of wetlands for agriculture. By 1941, global whooping crane numbers had sunk to a low of 22 birds. Of these, 16 birds comprised a migratory flock that bred at Wood Buffalo National Park in Canada and wintered at the Aransas National Wildlife Refuge in southern Texas. A remnant population of six non-migratory whooping cranes existed in Louisiana, but by 1949 this population died out.
Human activities, such as poaching and development, continue to be chief threats to whooping cranes. Their migration corridor is undergoing continuous industrial development, causing incidents such as fatal collisions with power lines. During the breeding season, a drought or bad storm could destroy eggs and newly hatched chicks. On the wintering grounds, oil and chemical pollution in the bays along the Texas coast could destroy the remaining habitat, while a hurricane could wipe out the entire flock. In the winter of 2000/2001, there were approximately 180 birds in the Wood Buffalo-Aransas flock.
Research and Recovery
In the late 1940s, government agencies in Canada and the United States began actively sharing data and expertise to prevent the extinction of the whooping crane. In 1967, the Canadian Wildlife Service and the U.S. Fish and Wildlife Service launched a whooping crane captive-breeding program for release into the wild. Scientists transported eggs from Wood Buffalo National Park by air 3,453 kilometers (2,145 miles) to the Patuxent Wildlife Research Center in Laurel, Maryland. In 1989, a whooping crane breeding facility was established at the International Crane Foundation in Wisconsin.
Canadian biologists created a captive-breeding facility at the Calgary Zoo in 1993, the same year U.S. officials began establishing a non-migratory flock in Florida using cranes from the U.S. and Canadian facilities. In 1996, after 230 eggs had been collected, biologists discontinued egg collection for captive rearing. The flock in Florida numbers about 80 birds, but has yet to successfully raise young. In the spring of 2000, one pair hatched two eggs, the first whooping crane eggs to hatch in the wild in the United States in 60 years. One of the chicks died within two weeks. The parents raised the other to fledging age, before it fell prey to a bobcat.
Since 1990, the United States has helped Canadian scientists conduct aerial surveys on the cranes' reproductive success on the nesting grounds in Wood Buffalo National Park. In the spring of 2000, they discovered 50 nests, tying the record for the most ever found in one spring. In 1993, scientists began tracking sandhill crane migratory routes to identify their wintering areas and determine whether sandhill cranes could be used as guide birds for whooping cranes. Since 1993, scientists have been using ultralight aircraft to teach a specific migration route to surrogate sandhill cranes. Biologists also initiated studies into potential crane reintroduction habitat in Manitoba, Saskatchewan, and Wisconsin, hoping to eventually establish a new Wisconsin-Florida migratory flock of whooping cranes.
For 15 years, Canada and the United States have conducted formal joint recovery efforts. In 1985, the two countries signed a Memorandum of Understanding (MOU) to improve coordination and joint cooperation in whooping crane conservation. The document has been renewed in 1990 and 1995. The 1995 renewal confirmed a goal of increasing whooping crane numbers in the Wood Buffalo-Aransas flock to one thousand individuals (an objective first established in the species' 1994 U.S. recovery plan). Officials expect to renew the MOU in 2001. In 1996, Canada and the United States formed a joint Whooping Crane Recovery Team that meets once every year or two. The team consists of five members from each country. Whooping crane recovery plans in the two countries are currently being combined into a single plan.
Piping Plover (Charadrius melodus)
Status
Canada (COSEWIC): Endangered
U.S. (USFWS): Endangered (Great Lakes population); Threatened (Atlantic Coast and Northern Great Plains populations)
Photo U.S. Fish and Wildlife Service
Description
The piping plover is a small, stocky, sandy-colored bird with yellow-orange legs, and resembles a sandpiper. In summer, the plover develops breeding plumage with a black band across the forehead from eye to eye and a black ring around the base of its neck. In winter, these marks are absent (see photo). Like other plovers, it runs in short bursts. The bird derives its name from its call notes, plaintive bell-like whistles that are often heard before the bird is seen.
Ecology
Piping plovers arrive on their breeding grounds during mid-March through mid-May and leave again by late August. They breed on the northern Great Plains, including the Canadian prairies, and along the Atlantic coast from Newfoundland to North Carolina. They also breed along the U.S. shores of the Great Lakes. They winter on the Atlantic and Gulf of Mexico coasts from North Carolina to Mexico, in the Bahamas, West Indies, and in Cuba. In 1996, there were nearly 6,000 breeding individuals throughout the plover's range, including 20 States, 9 Provinces, and the French islands of St-Pierre-Miquelon off Newfoundland's southern coast.
Piping plovers lay three to four eggs in shallow depressions lined with light-colored pebbles. The eggs are speckled with dark brown or black spots that make them scarcely distinguishable from the pebbles. Both partners incubate the eggs, which hatch within 26 to 28 days. Both sexes also tend to the chicks during feeding and resting, and continue to safeguard them until they can fly, at about 25 days.
Causes of Decline
Historically, habitat loss and degradation due to coastal development were the major contributors to this species' decline. The plover is now threatened largely by predation. Gulls, crows, raccoons, and skunks (all predators that thrive around human development) prey on plover eggs and young. Another significant threat is from human recreation. Walking, jogging, and operating vehicles on beaches prevent plovers from feeding, flush them from roost sites, and destroy camouflaged eggs. Similar threats face the plover on its wintering grounds.
Research and Recovery
Since 1988, Canadian and U.S. wildlife experts have shared information regularly about piping plover conservation strategies, such as beach guardian programs. Scientists exchange technical knowledge on banding, capture techniques, census methods and results, predator management, and all aspects of management of breeding and wintering populations. An International Piping Plover Coordination Group, comprised of Canadian and U.S. biologists, also facilitates information exchange and is coordinating recovery efforts.
This exchange of information has led biologists in both countries to employ innovative recovery methods. In breeding areas, experts direct human traffic around the fragile nests on beaches and erect wire fencing around nests to keep predators out. On the Great Plains water bodies, such as the Missouri River in the United States and Lake Diefenbaker in Canada, officials try to maintain water levels conducive to plover nesting. The two countries also exchange biologists to assist with specific projects. The United States sent two biologists to Canada in the mid-1990s to help resolve problems with predator exclosures in Nova Scotia. In 1998, a Canadian biologist participated in a review of wintering habitat issues in Texas. In 1994, the United States sent four biologists to help census plovers in Atlantic Canada.
In 1991 and 1996, wildlife officials from each country participated in two international censuses of breeding and wintering plovers. These censuses gave the first global population counts for the plover. More than a thousand biologists and volunteers from several countries participated in the census, including many government agencies and conservation groups. The results indicated that the plover's status remains precarious due to its low population numbers, sparse distribution, continued threats to habitat, and low reproductive success throughout its range.
Marbled Murrelet (Brachyramphus marmoratus)
Status
Canada (COSEWIC): Threatened
U.S. (USFWS): Threatened (California, Oregon, Washington)
Photo John Deal
Description
The marbled murrelet is a quail-sized bird with a plump body. It swims with its bill pointed upward, and flies in zigzags low over the water. Like most migratory birds, the marbled murrelet has different breeding and wintering plumages. The breeding plumage is dull brown on top, with "marbled" brown and white underparts. In winter, the bird is black with white on its throat, white shoulder patches, and white underparts. In autumn, the young resemble the adults in winter plumage, but the underparts have fine dusky bars.
Ecology
The marbled murrelet is an unusual seabird. It prefers to nest high in the well-hidden canopy of old-growth forests. By contrast, most seabirds nest in large colonies in burrows and crevices on offshore islands. In the northern part of its range, the murrelet nests in trees but also on the ground in treeless areas. Each May, adult marbled murrelets fly inland as far as 80 kilometers (50 miles) to nest. The birds are solitary nesters, and lay their single egg in a cup-shaped depression in thick mosses found on large branches. Both males and females incubate the egg in 24-hour shifts. While one incubates the egg, the other stays on the ocean, and flies back to the nest to feed the chick and change places with its mate. Once the egg hatches, they change places and feed the chick more frequently. The exchanges are most common in the early morning and in the evening. After the nesting season, marbled murrelets fish the coastal waters of the North Pacific throughout the fall. In more northern latitudes, they are usually forced farther out to sea in the winter by coastal ice formation and the limited availability of small fish.
Causes of Decline
In the United States, the marbled murrelet occurs along the Pacific coast from the Canadian border to northern California, as well as in Alaska. In Canada, it is found off the coast of British Columbia and around coastal lakes. The estimated population is 301,000 in the United States and 50,000 to 60,000 in Canada. Major threats to the marbled murrelet are oil spills, their incidental catch in commercial fishery nets, and the destruction of habitat due to timber operations. Old-growth forest harvesting removes the bird's nesting habitat, while the toxic effects of leaked oil have directly killed thousands of marbled murrelets.
Research and Recovery
Since the mid-1980s, Canadian and U.S. wildlife biologists have cooperated on marbled murrelet conservation and recovery issues. In 1972, scientists created an international organization called the Pacific Seabird Group to undertake seabird research and conservation. The group established a Marbled Murrelet Technical Committee in 1988 that includes Canadian and U.S. representatives. The committee meets annually to share information on recovery issues and the conservation status of marbled murrelets in the United States and Canada. The committee coordinates an ongoing effort to develop and update an inland survey protocol for marbled murrelets in British Columbia, California, Oregon, and Washington. Marbled murrelets are secretive and difficult to detect at inland forest stands, and a reliable survey technique is important for identifying nesting areas.
In Canada, scientists are also focusing recovery efforts on searching for murrelet nesting sites. Officials impose interim habitat protection measures in areas where nests are known to exist. Various forest companies on Vancouver Island have voluntarily deferred harvesting old-growth habitats used by marbled murrelets. As part of the U.S. and Canadian recovery efforts, biologists are emphasizing the need to reduce marbled murrelet mortality from net fisheries in the marine environment. The U.S. Fish and Wildlife Service and the Canadian Wildlife Service are collaborating to devise methods to assess the number of marbled murrelets caught in commercial fishing nets, and subsequently to reduce the incidental net entanglement of marbled murrelets.
