Pollution & Contamination

Many bird species numbers have declined to dangerously low levels. Currently, 91 North American bird species are Federally-listed as threatened or endangered species. Pesticides and other environmental contaminants are considered to be contributing factors to these declines.

In addition to being responsible for protecting threatened and endangered species ( Endangered Species Act), the Service also is responsible for enforcing the  Migratory Bird Treaty Act. These two laws combined offer protection to virtually all bird species. The Service's Division of Environmental Contaminants plays an important role in protecting and recovering bird species. Here are some examples of the types of roles we play:

Bald Eagle

The bald eagle once ranged throughout every state in the Union except Hawaii. When America adopted the bird as its national symbol in 1782, as many as 100,000 nesting bald eagles lived in the continental United States, excluding Alaska. By 1963, only 417 nesting pairs were found in the lower 48 states. Today, as a result the banning of the pesticide  DDT and Service recovery efforts in partnership with other Federal agencies, tribes, State and local governments, conservation organizations, universities, corporations, and many individuals, this number has risen to almost 10,000 nesting pairs of bald eagles.

Contaminants biologists are involved in monitoring bald eagle populations and assisting in recovery activities. Some examples include in evaluating contaminant affects on eagle reproduction in  Maine, evaluating the potential impacts of a landfill expansion on eagles in  New York, and determining why eagle breeding success continues to be low along the  Columbia River in Oregon and Washington and the  Hood Canal in Washington.

Peregrine Falcon

The peregrine falcon is one of nature's swiftest and most beautiful birds of prey. Its name comes from the Latin word peregrinus, meaning "foreigner" or "traveler.&" This impressive bird has long been noted for its speed, grace, and aerial skills. As with the bald eagle, DDT was a major factor in the decline of the peregrine falcon which was listed as an endangered species in 1970. Now, the peregrine is a symbol of America's recovering threatened and endangered species.  Monitoring contaminant threats to peregrines in Alaska

Spectacled Eider

In 1993, the spectacled eider, an arctic sea duck that sports a distinctive white eye patch, was listed as a threatened species under the Endangered Species Act due to its rapid decline on its primary breeding grounds on Alaska's west coast. After brief summers on Alaska and Russia tundra breeding grounds, the birds migrate to isolated wintering areas in the Beaufort, Chukchi, and Bering seas. When listed, the causes for the dramatic decline in Alaska birds had not been identified. The main threats to this sea duck on its breeding grounds are now thought to include: lead poisoning from eating spent lead shot; predation by foxes, gulls, and jaegers; and hunting and other human disturbances. Biologists are not certain what threats the eider faces at sea, but believe threats could possibly be linked to factors that are causing the decline of other Bering Sea species such as the Steller sea lion.  Lead and the Spectacled Eider.


In early June 1999, the U.S. Fish and Wildlife Service received reports of a large number (>20) of dead and dying ravens in the Sitka, Alaska area. Several carcasses were sent to the Service's  National Fish and Wildlife Forensics Lab in Ashland, Oregon, where results confirmed that the ravens died from poisoning by the insecticide Diazinon.  Full Story.

Black-Capped Chickadees

Since January 1998, approximately 300 black-capped chickadees (Poecile atricapillus) with grossly deformed bills have been reported in Alaska. Sightings have been clustered in Anchorage but distributed throughout south-central Alaska. The Service, along with the US Geological Survey Biological Resource Division, is conducting a study to determine the cause of the deformed bills.  Full Story.

Mercury Contamination in Waterbirds Breeding in San Francisco Bay

San Francisco Bay has a legacy of mercury contamination from historical mercury mining in the Coast Range and gold extraction in the Sierra Nevada.

In a large collaborative project funded by the CalFed Ecosystem Restoration Program, biologists of the U.S. Geological Survey, U.S. Fish and Wildlife Service, San Francisco Bay Bird Observatory, and PRBO Conservation Science are investigating the risks of mercury to waterbirds breeding within the estuary.

 Mercury Contamination in Waterban Francisirds Breeding in Sco Bay. From the Don Edwards San Francisco Bay National Wildlife Refuge quarterly newsletter - Tideline

Oil Field Waste Pits

In 1997, the U.S. Fish and Wildlife Service (Service) estimated that 2 million migratory birds were lost each year to  oil pits throughout the United States. Since 1997, many oil operators have taken measures to prevent migratory bird and other wildlife mortality in oil field waste pits. Currently, an estimated 500,000 to 1 million birds are lost annually in oil field production skim pits and  centralized oilfield wastewater disposal facilities(Trail 2006). Pits and open tanks are commonly used to separate any water that is extracted from an oil-bearing formation along with the oil. Ineffective separation of oil and water results in wastewater covered by a layer of oil, creating a death trap for migratory birds and other wildlife. Service Environmental Contaminants and Law Enforcement staff have played a crucial role in reducing the number of problem oil pits.  Full Story.

 Oil Pits 

Last Updated: September 22, 2015