QUESTIONS AND ANSWERS
DOUBLE-CRESTED CORMORANT MANAGEMENT
Q. What is a
A. The double-crested
cormorant (Phalacrocorax auritus) is a long-lived, colonial-nesting waterbird native to
. One of 38 species of cormorants worldwide,
and one of six species in
, it is usually found in flocks, and is sometimes confused
with geese or loons when on the water.
Double-crested cormorants can be found in many locations throughout
, including along the coast and inland on
lakes, rivers, and other water bodies. The largest concentrations of double-crested
cormorants are found on the
and the lakes of the Canadian
Q. How do they
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. Typically, 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
will accompany adults to feed at 7 weeks. They are independent of the adult
birds at 10 weeks.
Q. What about their population?
double-crested cormorant is the most abundant of six species of cormorants
. The Service estimates that the current
continental population of double-crested cormorants is 2 million birds, with
nearly 70 percent of this number in the Interior population centered around the
and the prairie region of central
. While the total North American
population increased rapidly from the 1970s into the 1990s, more recent
estimates have indicated that the overall rate of growth in the
slowed during the early 1990s. For the U.S. as a whole, according to
Breeding Bird Survey trends, the breeding population of double-crested
cormorants increased at a rate of approximately 7.9 percent per year from
Q. Will the
population continue to increase?
A. The total population
will continue to increase in the short term although at a slower rate than in
past years. In the long term, the population will likely stabilize due to
factors such as disease, lack of available nesting habitat, or limitations on
food resources. Because cormorants are not typically preyed upon by other
species, their populations are regulated primarily by these factors rather than
double-crested cormorants protected in the
double-crested cormorants are one of approximately 800 species protected under
the Migratory Bird Treaty Act of 1918, and subsequent amendments. This act was
first passed to implement the terms of a treaty between the
for the protection of migratory birds.
Excessive market hunting of migratory birds prompted this treaty, which was
later followed by treaties with
. Double-crested cormorants were first
protected in 1972 through an amendment to the Mexican treaty.
Q. What do
double-crested cormorants eat?
A. They eat
mainly 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 cormorant’s diet can vary
considerably from site to site and throughout the year.
double-crested cormorants negatively impact fish populations in open waters?
A. Cormorants are
one of many factors, such as water quality, aquatic habitat, predation, and
angler catch, that can affect fish populations. Recently, U.S. Fish and Wildlife Service
biologists conducted an extensive review of published studies, most of which
indicated that fish species valued by sport and commercial anglers make up a
small proportion of the cormorant’s diet. But there are exceptions to this rule and, in some cases, cormorants appear to be capable of taking numbers of sport fish significant
enough to have a negative impact on catch rates. For example, recent research studies
have revealed that summer resident and
migrating cormorants can diminish the number of fish of catchable size available to anglers. Future
research in this area is needed to improve our understanding of the
relationship between cormorants and their prey populations.
double-crested cormorants significantly affect vegetation and other birds?
A. Cormorants do kill trees, shrubs, and other
vegetation, due to accumulation of their guano, which is highly acidic, and
removal of foliage for nesting material. If the species of vegetation being damaged is common, the ecological
significance of such damage will be limited, although aesthetic concerns may
exist. However, cormorant damage can be
ecologically significant, as is the case on some
islands where cormorants are causing
severe damage to Carolinian vegetation, the rarest type of vegetation in the
. In regard to impacts on other colonial waterbirds by cormorants, evidence of locally-significant impacts has been observed by many
biologists, particularly in the
Q. Does the
Fish and Wildlife Service control
double-crested cormorants when they cause damage?
A. The Service’s primary role in double-crested cormorant
management is to oversee, coordinate, and authorize control activities
conducted by individuals and agencies. We authorize the take of cormorants either through the issuance of
depredation permits or under the authority of depredation orders. Permits allow the permittee to take cormorants, their eggs, and nests in order to alleviate specific damages.
Such permits are issued only after the individual or agency 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. Before issuing
a permit, the Service determines that any authorized take has a reasonable
chance of resolving the damage, and that the take will not have a significant
negative impact on the migratory bird resource. The Service could undertake control of cormorants on lands that it owns,
such as National Wildlife Refuges and National Fish Hatcheries, but it normally
would not conduct cormorant management activities on other public or private
Q. Does the
Fish and Wildlife Service allow the control
of double-crested cormorants at aquacultural facilities?
A. Yes. Since
1998, under a depredation order (50 CFR 21.47), the Service has permitted the
lethal take, without a Federal permit, of double-crested cormorants at
commercial freshwater aquaculture facilities and State-owned hatcheries in 12
southeastern States and Minnesota when non-lethal methods are ineffective at
preventing depredation. In the final rule, the aquaculture depredation order
was expanded to allow USDA Wildlife Services officials to conduct winter roost
control to prevent cormorant depredation at fish farms. Federal and State hatchery managers will also
be allowed to control depredating cormorants.
Q. If the
Fish and Wildlife Service doesn’t control
cormorants, then who does?
permits can be issued to private landowners or to public agencies (such as
State fish and wildlife agencies). While
these individuals and agencies can implement control themselves, according to
the stipulations of their permit, these entities may request the assistance of experts
from the USDA Wildlife Services program. USDA Wildlife Services is responsible for providing Federal leadership
in managing problems caused by wildlife and provides assistance to agencies,
organizations, and individuals in resolving wildlife damage problems on both
public and private lands. They provide recommendations first for a variety of
non-lethal management options, including harassment and habitat alteration. If
these activities prove ineffective, USDA Wildlife Services may recommend lethal
take of migratory birds.
Q. How are the
State fish and wildlife agencies involved?
A. State agencies
generally oversee on-the-ground management of wildlife in their states. Because
of the Migratory Bird Treaty Act, cormorants are a trust responsibility of the
U.S. Fish and Wildlife Service. Thus, in
order for the States to take cormorants, they must be issued a depredation
permit or have authority under a depredation order. In recent years, in the
basin, the States of New York and
have received depredation permits for
cormorant control activities. The U.S. Fish and Wildlife Service issued these
permits, upon the recommendations of USDA Wildlife Services, to reduce
competition with other colonial waterbirds, including
common terns and black-crowned night herons. In addition, the New York
Department of Environmental Conservation has received authority to shoot
cormorants at fish stocking sites in
is also working with USDA Wildlife
Services to harass cormorants from the lake during the fall migration. Under
the new regulations, State fish and wildlife agencies (in 24 States) will be able
to conduct activities such as these without a depredation permit, under the
terms and conditions of the public resource depredation order.
management alternatives were analyzed in the final EIS?
A. The Service analyzed the impacts of six separate
alternatives in relation to their ability to reduce resource conflicts
associated with double-crested cormorants, increase management flexibility, and
conserve healthy populations of double-crested cormorants. Those alternatives
Alternative - Under this alternative,
existing wildlife management policies and practices would continue. These policies and practices include
non-lethal management techniques such as harassment and habitat modification,
the issuance of depredation permits, and continuation of the aquaculture depredation
order. No additional regulatory methods
or strategies would be authorized.
Management Alternative - Under this
alternative, depredation permits to allow the lethal take of cormorants, their
eggs, or their nests would not be authorized. To reduce impacts associated with cormorants, this option would allow only non-lethal management techniques such as
harassment, habitat modification, exclusion devices at production facilities,
and changes in fish stocking practices.
Increased Local Damage
Control Alternative - This alternative
would expand the current cormorant depredation policy to address a broader
range of resource conflicts. The aquaculture depredation order would continue
to allow double-crested cormorants to be killed at commercial freshwater
aquaculture facilities and state-owned fish hatcheries in 13 states, and would
be expanded to include winter roost control at aquacultural facilities in those states. Lethal
control of double-crested cormorants would be authorized at State and Federal
fish hatcheries. Population monitoring on breeding grounds would be conducted
at regular intervals.
Public Resource Depredation
Order Alternative (Preferred Alternative) This alternative would establish a new public resource
depredation order authorizing certain public agencies to implement a cormorant
management program, while maintaining Federal oversight of cormorant
populations via reporting and monitoring requirements. Control activities under
authority of this new depredation order must be intended to alleviate damages
to public resources such as fish, wildlife, and vegetation. The aquaculture
depredation order would be expanded to allow winter roost control by USDA
Wildlife Services professionals. Lethal
control of double-crested cormorants would be authorized at State and Federal
fish hatcheries. Depredation permits
would continue to be used to address conflicts not covered under the
depredation orders. Population monitoring on breeding grounds would be
conducted at regular intervals.
Reduction Alternative - This alternative
would require development of regional cormorant population objectives designed
to help reduce damages. Control would be carried out at nesting, roosting,
wintering and other sites. A special
statewide cormorant permit would be issued by the Service to each State
choosing to engage in cormorant population reduction efforts. States could then designate other agents to
carry out control. The aquaculture depredation order would be expanded to allow
winter roost control. Population monitoring on breeding grounds would be
conducted at regular intervals.
Alternative - Under this alternative,
frameworks to develop seasons and bag limits for hunting double-crested
cormorants would be established jointly by federal and state wildlife
agencies. In addition, the depredation
policy outlined in the Increased Local Damage Control Alternative, above, would
address continuing conflicts (e.g., via issuance of depredation permits and the
aquaculture depredation order). Population monitoring on breeding grounds would be conducted at regular
Q. Why did the Service select Alternative D as the preferred
A. Both scientific evidence and evidence based on observations made
by resource professionals indicate that double-crested cormorants can and do
have significant biological and economic impacts and that, because of
increasing cormorant populations, the threat and/or magnitude of these impacts
is greater today than it was 30 years ago. Since cormorant conflicts with public resources tend to be highly
localized, it makes sense to give more cormorant management authority to the
agencies that are best-suited to address local problems, while maintaining a
degree of Federal oversight through reporting and evaluation requirements.
Q. What is the relationship
between the Environmental Impact Statement and the rulemaking?
A. The final rule and the final
EIS are separate but related documents. “Rulemaking”
is the process by which Federal agencies promulgate regulations to implement
decisions. An EIS helps the agency
consider the environmental aspects of their decisions, as well as involving the
public in the decision-making process. The preferred alternative outlined in
the final EIS required us to amend the section of the Code of Federal
Regulations governing the issuance of migratory bird permits. We did this through the rulemaking process by
first issuing a proposed rule for public comment and then by publishing the
Q. Are there any differences between the proposed rule and the
A. Yes. The months during which winter
roost control is allowed were extended to include April; Section 7 consultation
“conservation measures” to protect threatened and endangered species were added;
specific suspension and revocation procedures were added; the OMB information
collection approval number (1018-0121) and expiration date were added; an advance
notification requirement for take of >10% of a breeding colony was added; and
monitoring and evaluation requirements were modified. These changes were made in response to public
and agency comments or to satisfy procedural requirements.
Q. How does the final rule
differ from current management policy for double-crested cormorants?
A. Currently, anyone who
has problems with double-crested cormorants must apply for a Federal permit in
order to lethally take birds, their eggs, or their nests. The only exception is for aquaculture and
State hatchery producers in 13 States, who fall under the authority of the
aquaculture depredation order and may, in certain
circumstances, take double-crested cormorants without a Federal permit. The final rule changes policy so that State
fish and wildlife agencies, Federally recognized tribes, and USDA Wildlife
Services, in 24 States, can take cormorants without a Federal permit when they
are causing damage to public resources such as fish (including hatchery fish),
wildlife, plants, and their habitats. Additionally, USDA Wildlife Services officials will be able to conduct
control at winter roost sites, in 13 States, to prevent cormorant depredation
and Federal and State hatchery managers in those States will be allowed to
Q. How will the Service keep track of double-crested cormorant
populations to ensure that they remain at sustainable levels?
A. Population monitoring provides critical information about
population change and tells managers the present population status of
species. Cormorant population monitoring
is conducted by the Service, USDA Wildlife Services, the Canadian Wildlife
Service, the States, and various universities. The U.S. Geological Survey and various non-governmental organizations
participate in recording and analyzing the population data. The various types of surveys include the
Great Lakes Colonial Waterbird Survey, Atlantic Coast
Colonial Waterbird Survey, winter roost surveys,
Christmas Bird Counts, and Breeding Bird Surveys. Additionally, in the final rule, agencies
that conduct local population control are required to evaluate the effects of
their actions on double-crested cormorant populations and annually report their
findings to the Service.
Q. What are the reporting requirements associated with the final
A. Each year, agencies acting under
authority of the public resource depredation order must provide the appropriate
Service Regional Migratory Bird Permit Office with a report detailing
activities conducted under the authority of this order (as specified in the
Agencies must, before they initiate control activities in a given year,
provide a one-time written notice to the appropriate Service Regional Migratory
Bird Permit Office. If any Agency plans control action(s) that would take more
than 10% of a cormorant breeding colony it must first provide written
notification with information about the proposed activity (at this level of
control, the Regional Director may prevent the activity from taking place).
For actions that are conducted with the intent of reducing or
eliminating local double-crested cormorant populations, Agencies must:
carefully plan activities to avoid disturbance of nontarget species, evaluate effects of their management activities on cormorants at the
control site, evaluate effects of their management activities on the public
resources being protected and on nontarget species;
and include this information in their annual report. The Service will
prepare annual reports summarizing regional and national double-crested
cormorant management efforts.
Q. What happens next?
A. The new regulations will
not be effective until 30 days following publication of the final rule and
Record of Decision in the Federal Register. Thus, the effective date will be
November 7, 2003
. This waiting period allows the public and agencies to become familiar
with the new regulations before implementing any actions.
Q. Can I obtain information on the Internet on double-crested
cormorants and what is being done to manage them?
A. Yes, online information is available at several websites:
Fish and Wildlife Service Division of
Migratory Bird Management:
Department of Agriculture APHIS Wildlife
Canadian Wildlife Service:
New York State Department of Environmental Conservation:
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