WASHINGTON - February 5 - Recent studies have shown that the ivory gull's population has drastically decreased and is continuing to fall. The latest survey by the Canadian Wildlife Service in 2005 found a 90 percent drop, and experts question whether global warming is to blame. In fact, the decline in ivory gull numbers in the North American population has been steeper and more rapid than in polar bears, which the U.S. Fish and Wildlife Service proposed in December to list under the Endangered Species Act (ESA).
"The ivory gull populations throughout the Arctic are decreasing, but in North America there are quite possibly even fewer ivory gulls now than there are of the better-known and more recognized polar bears," says Chris Haney, chief scientist for Defenders of Wildlife.
Chapter two of Defenders' global warming series, "Navigating the Arctic Meltdown," addresses the unique challenges that ivory gulls face in their rapidly changing Arctic environment. The report also offers steps that can be taken now that will result in long-term benefits for recovering ivory gull populations.
This sea bird, one of the least known and rarest in North America, relies on the sea ice and glaciers near the shore for both foraging for food and breeding. With the shrinking and dramatic movement of pack ice floes due to global warming, it is becoming increasingly difficult for the ivory gull to find food and keep their nesting sites safe from predators.
"Wholesale retreat of the sea ice pack from shore is an immediate threat," says Haney. "Ivory gulls depend entirely on edges of sea ice to find food. Although these are sea birds and they can certainly swim, the pack ice enables them to roost close to their preferred foraging sites, thereby avoiding the extreme heat loss that would result from lengthy immersion if resting only in the frigid waters."
The disappearance of natural barriers that keep the ivory gull safe, especially during the breeding season, is yet another dilemma. Most ivory gull colonies are located well inland on small outcrops of barren rock surrounded by glaciers. These isolated havens are meant to keep other birds and predators, such as the arctic fox, away. However, these ice fields and glaciers have shrunk by 15 percent to 20 percent since the 1960s, and as these barriers melt away, the colonies are more exposed to predators.
The decline of the polar bear that Defenders discussed in chapter one of this series is also linked to the decline of the ivory gull. Experts differ as to the extent to which these gulls depend on polar bear kills for scavenging, but there is consensus that some of the ivory gull's food supply comes from these opportunistic sources. Given that polar bear declines have already led to the U.S. Fish and Wildlife Service proposing to list the polar bear as threatened under the ESA, the loss of this important food-generating predator in the Arctic ecosystem creates an additional strain on the ivory gull. Loss of Arctic habitat, at least some food sources, undue predation and other threats, especially very high concentrations of mercury, combine to place huge stresses on ivory gulls.
"The most important step in saving the ivory gull and all Arctic species affected by global warming is for Congress to pass strong legislation that will reduce emissions of greenhouse gasses nationwide," says Rodger Schlickeisen, president of Defenders of Wildlife.
Regulating the emission of carbon dioxide and other greenhouse gasses is one long-term solution that will benefit all species on the planet. In addition, in its report on ivory gulls, Defenders offers several actions that can be taken immediately to conserve ivory gulls.
First, international research funding is needed to better assess and respond to the particular threats that this species faces. Coordinated monitoring surveys are urgently needed in Canada, Greenland, Norway and Russia. Given the alarming population nosedive happening in Canada, it is critically important to know what is happening to all of the world's other ivory gull colonies.
Second, protecting breeding colonies from undue disturbance is necessary to preserving and recovering the ivory gull. All current and known past ivory gull breeding colonies should be protected from disturbances, particularly from motorized vehicles, such as all-terrain vehicles,, motorboats and low-flying aircraft. Also, other types of disturbances, including construction and pollution associated with oil and mineral exploration, and even tourism, should be minimized.
Third, mortality of ivory gulls from subsistence hunting should be reduced. While the Inuit have the legal right to hunt ivory gulls, they rarely pursue them actively. Ninety percent of recovered bands in fact come from Greenland or Nunavut where researchers believe that ivory gulls may be shot because they are mistaken for a more common species. Stricter law enforcement and continuing the extensive public education in Canada and Greenland are two key components to curbing unsustainable take that could have a disastrous impact on the future of the ivory gull.
"While it may take up to 100 years to fully reverse the harm we've already done to the earth's climate, we can all do something today to step up our efforts to preserve Arctic wildlife," concludes Schlickeisen.
The first two chapters of "Navigating the Arctic Meltdown," and subsequent installments as they become available, can be found at www.defenders.org/globalwarming.