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DOUBLE-CRESTED CORMORANT QUESTIONS AND ANSWERS Q. What is a double-crested cormorant? A. The double-crested cormorant (Phalacrocorax auritus) is a long-lived, colonial-nesting waterbird native to North America. One of 38 species of cormorants worldwide, and one of six species in North America, it is usually found in flocks, and is sometimes confused with geese or loons when on the water. Q. Where do they live? A. Double-crested cormorants can be found in many locations throughout North America. They nest along the coast from southwest Alaska to Mexico, and on lakes from central Alberta, James Bay and Newfoundland, south along the coast to the Gulf of Mexico. Along the Pacific coast and the southern Atlantic coast, populations are resident year-round. Cormorants spread from the interior of North America into the Great Lakes between 1913 and the early 1930s. The Great Lakes basin population migrates along the Atlantic coast and Mississippi River drainage, to overwinter in the southeastern Gulf states and Gulf of Mexico, returning north in April. Q. How do they nest? A. Cormorants breed in colonies ranging from several pairs to a few
thousand. They build their nests of twigs and branches beginning in April,
usually in trees or on the ground, on islands favored also by other colonial
nesting birds, like great blue herons, great egrets, black-crowned night-herons,
cattle egrets, gulls, and terns. At age three or four, adults are ready
to breed. Eggs are laid in mid-to-late April, and hatching occurs approximately
25 days later. A typical nest has two or three chicks. These chicks can
fly at 5-6 weeks and accompany adults to feed at 7 weeks. They
Q. What about their population? A. The size of the North American breeding population of the double-crested cormorant has been estimated at about 372,000 pairs, or 852 colonies. Using values of one to four non-breeding birds per breeding pair yields an estimated total population of 1-2 million birds. The double-crested cormorant breeds widely throughout much of the coastal and interior portions of the United States. It has been found breeding in 46 of the 48 contiguous United States. However, it is not uniformly distributed across this broad area. Sixty-one percent of the breeding birds belong to the Interior population and it is the fastest growing of the six major North American breeding populations. From 1970-1991, in the Great Lakes region (American and Canadian), which lies within the range of the Interior population, the number of double- crested cormorant nests increased from 89 to 38,000, an average annual increase of 29 percent. For the contiguous United States as a whole, the breeding population increased at an average rate of 6.1 percent per year from 1966-1994. Q. Will the population continue to increase? A. The total population will probably continue to increase in the short term. In the long term, the population will likely decline and then stabilize due to disease, lack of available nesting habitat, or changes in food resources. Because cormorants are not typically preyed upon by other species, their populations are regulated primarily by these other factors. Q. What do double-crested cormorants eat? A. They eat fish. Adults eat an average of one pound per day, usually
comprised of small (less than 6 inch) bottom dwelling or schooling "forage"
fish. They are opportunistic and generalist feeders, preying on many species
of fish, but concentrating on those that are easiest to catch. Because
the ease with which a fish can be caught depends on a number of factors
(distribution, relative abundance, behavior, etc.), the composition of
a
Q. Do double-crested cormorants eat brown and lake trout, steelhead, and salmon? A. Yes, particularly when they are small. Recently stocked schools of
hatchery fish of these species are most at risk. Cormorants are attracted
to these fish, as are large predatory sport fish. After these stocked fish
disperse in the lake, they are much less likely to be eaten by a cormorant.
In fact, fish species valued by sport and commercial anglers make up a
very small proportion of the cormorant's diet in open lake waters. Additional
research will help scientists learn more about this important issue.
Q. Do double-crested cormorants significantly affect fish populations in open waters? A. This is an important question without a definitive answer at this
time. The perception among anglers in some locations is that cormorants
are to blame for decreases in catch. However, according to dietary studies
of cormorants on New York's Oneida Lake, summer resident and migrating
birds can diminish the number of catchable size walleye pike and yellow
perch available to anglers, but overall, cormorants are not a threat to
the continued viability of these fish populations. On Lake Champlain, studies
indicate yellow and white perch are the main prey species for cormorants.
However,
However, studies conducted last year by the New York State Department
of Environmental Conservation and the U.S. Geological Survey implicate
predation by double-crested cormorants in the decline of smallmouth bass
in the eastern basin of Lake Ontario. Those studies constitute the
first scientific evidence provided to the Agency suggesting any significant
effects in open waters of cormorant predation on a sportfish species. In
light of these studies, it is plausible that cormorants can have an effect
on
Q. Do double-crested cormorants eat the bait or forage fish required by sport fish to survive? A. Yes, they eat the same bait or forage fish consumed by sport fish
like trout, salmon, walleye pike and bass. A variety of research conducted
in the Great Lakes suggests that cormorants consume less than 10 percent
of the total amount of forage fish available. This consumption has not
been demonstrated to affect sport fish populations. Recent research in
Lake Erie indicates that all the forage fish consumed by cormorants amounted
to only about one percent of the forage fish needed to support populations
of
Q. Are cormorants protected in the U.S.? A. Yes, double-crested cormorants are one of approximately 800 species
protected under the federal Migratory Bird Treaty Act of 1918, and subsequent
amendments. This act was first passed to implement the terms of the convention
between the U.S. and Great Britain (on behalf of Canada) for the protection
of migratory birds. Excessive market hunting of migratory birds prompted
this convention, which was later followed by conventions with Mexico, Japan,
and Russia. Cormorants were first protected through an amendment to the
Mexican convention in 1972. Because cormorants are
Q. Does the U.S. Fish and Wildlife Service control the number of double-crested cormorants when they cause damage? A. In part. The Service's primary means in limiting double-crested cormorants
is through the issuance of depredation permits under the Migratory Bird
Treaty Act. These permits enable others to take cormorants and/or their
eggs and nests in order to alleviate damage. Such permits are issued only
after the landowner or management authority has applied for a permit, has
demonstrated that damage has occurred, and has tried a variety of non-lethal
management activities which have proven ineffective on their own.
Before issuing a permit, the Service determines that any authorized
As a landowner, the U.S. Fish and Wildlife Service could undertake control of cormorants on Service-owned lands--like National Wildlife Refuges. If this were determined necessary to protect endangered or threatened species, or other species of management concern, the Service could do this under the authority of the Migratory Bird Treaty Act. The Service would not normally conduct cormorant management activities on other public or private lands. Q. If the U.S. Fish and Wildlife Service doesn't control cormorants, then who does? A. Landowners are the persons most often responsible for taking migratory birds causing damage to their private property. They can do so only after obtaining a depredation permit from the Service. Alternatively, wildlife management authorities can apply for a permit. Typically state fish and wildlife agencies apply for depredation permits to take migratory birds causing damage to public resources, including other natural resources such as endangered species. Q. What is the role of the U.S. Department of Agriculture? A. The U.S. Department of Agriculture's Wildlife Services program is responsible for providing federal leadership in managing problems caused by wildlife. USDA/Wildlife Services provides assistance to agencies, organizations, and individuals in resolving wildlife damage problems on both public and private lands, including National Wildlife Refuges. They provide recommendations first for a variety of non-lethal management options, including harassment and habitat alteration. If these activities prove ineffective, the USDA/Wildlife Services may recommend a limited lethal take of migratory birds to supplement the non-lethal management activities. Before the U.S. Fish and Wildlife Service issues permits for lethal depredation activities to a landowner, a wildlife damage report must be submitted by the USDA/Wildlife Services in support of this recommendation. In addition to consultation, this agency also works under privately funded cooperative agreements to implement damage management programs on public and private lands. Q. How are the state fish and wildlife agencies involved? A. The state agencies oversee on-the-ground management of wildlife in their states. In the case of federally protected species, such as cormorants, any lethal takes must also be done under the jurisdiction of the U.S. Fish and Wildlife Service or USDA/Wildlife Services. In the Great Lakes basin, the States of New York and Vermont have
The states have also begun assessing the cormorant-fishery issue on a larger scale. Recently, the state agencies in the Great Lakes sponsored workshops on cormorant-fishery issues, in coordination with the USDA/Wildlife Services and the U.S. Fish and Wildlife Service. On Lake Champlain, the States of Vermont and New York, in cooperation with USDA/Wildlife Services, have completed an Environmental Assessment to further guide their lake-wide cormorant management activities. Q. Does the U.S. Fish and Wildlife Service currently issue depredation permits for cormorant control in order to protect sport fish in open waters, or the local economy supported by sport or commercial fishing? A. No. The Service issues depredation permits only when control is
Q. Does the U.S. Fish and Wildlife Service currently allow the control of double-crested cormorants at aquacultural facilities? A. Yes. Since 1998, the Service has permitted the killing, without federal permits, of double-crested cormorants at aquaculture facilities in 12 Southeast states and in Minnesota when non-lethal methods are ineffective in preventing depredation. Aquaculture producers in other states must apply for and operate under a federal permit to control cormorants if a need is demonstrated. Q. Has the U.S. Fish and Wildlife Service taken other actions to manage double-crested cormorants in addition to issuing depredation permits? A. Yes. The Service has periodically funded population surveys in coordination with states and the Canadian Wildlife Service to monitor the species throughout the Great Lakes basin. The Service has also funded and conducted food habit studies in order to determine the diet of cormorants at different locations in the Great Lakes, as well as a range-wide status assessment of the Great Lakes cormorant population in order to gather the biological information needed to develop a management plan. Q. What will be in the management plan? A. The plan will review the distribution and population status of double-crested cormorants, their positive values, damage and conflicts associated with them. It will also provide a detailed description of management objectives for cormorants, while describing approved measures for reaching those objectives. Q. How will the EIS relate to the management plan? A. The primary purpose of the EIS is to serve as a planning and decision-making document for federal officials, while allowing for public input into the process. The EIS process requires the Service to analyze and consider a wide range of management options in developing a management strategy, and also to respond to public comments about those options. Once the EIS is completed, the management option chosen by the service will form the foundation of a detailed management plan. However, the EIS and management plan processes are one and the same. Q. When will the EIS be completed? A. While no one can predict with certainty how long it will take to prepare the EIS, the Service plans to have it completed in the spring of 2001. All efforts will be made to complete the analysis and issue a decision in the shortest possible amount of time. Q. What management alternatives will be evaluated in the EIS? A. The Service will identify a series of management alternatives that will be evaluated in the EIS, based on public comments received during a public scoping process that begins with the publication of a Notice of Intent. Alternatives being considered for evaluation range from continuing present policies to implementing active management options such as harassment and nest destruction or large-scale population reduction. Q. What opportunities will there be for public comment? A. As part of the scoping process, the Service will host public meetings
at sites across the country to discuss potential management alternatives
and to gather public comments on those alternatives or other potential
remedies proposed by the public. Dates, locations and times of the
meetings have not yet been determined, but will be published in a future
Federal Register
Once the alternatives to be analyzed in the EIS are identified, the public will have an additional opportunity to comment on the draft EIS. The Service will respond to all substantive issues raised by public comments on the draft before publishing a final EIS and issuing a decision. Written comments on the scope of the EIS may be submitted by
Q. Can I obtain information on the Internet on double-crested cormorants and what is being done to manage them? A. Yes, on-line information is available at several websites: U.S. Fish and Wildlife Service/Office of Migratory Bird Management:
Canadian Wildlife Service:
U.S. Department of Agriculture/Wildlife Services:
U.S. Fish and Wildlife Service/Lake Champlain Fish and Wildlife Resources
Complex:
U.S. Geological Survey/Patuxent Wildlife Research Center:
News releases are also available on the World Wide Web at
Questions concerning a particular news release or item of
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