U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2007–3094

November 2007

Avian Influenza Surveillance of Wild Birds

Printed on recycled paper

The President’s National Strategy for Pandemic 

Influenza directs federal agencies to expand the 

surveillance of United States domestic livestock and 

wildlife to ensure early warning of highly pathogenic 

avian influenza (HPAI) in the U.S. The immediate 

concern is a potential introduction of HPAI H5N1 virus 

into the U.S. The presidential directive resulted in the U.S. 

Interagency Strategic Plan for Early Detection of H5N1 

Highly Pathogenic Avian Influenza in Wild Migratory 

Birds (referred to as the Wild Bird Surveillance Plan or 

the Plan). 

Background

The Wild Bird Surveillance Plan, implemented 

in March 2006, was developed by wildlife biologists, 

migratory bird specialists, veterinarians, and 

epidemiologists from the U.S. Department of Interior 

(DOI), Department of Agriculture, and Health and 

Human Services, along with the Association of Fish and 

Wildlife Agencies, the National Association of Public 

Health Veterinarians and the State of Alaska. The Plan is 

unprecedented in scope because of the number of agencies 

and organizations participating; the range of wild bird 

species being sampled—waterfowl, shorebirds, gulls and 

terns, among others; the number of wild birds tested; and 

the geographical coverage that includes all 50 states and 

six freely-associated states and territories in the Pacific 

Basin.

The Wild Bird Surveillance Plan consists of five 

sampling strategies: 

1. Wild Bird Morbidity/Mortality Investigations 

2. Live Bird Surveillance 

3. Surveillance of Hunter-Harvested Birds

4. Sentinel Birds Surveillance

5. Environmental Sample Testing 

HPAI Early Detection Database System 

—HEDDS

The Wild Bird Surveillance Plan also called for the 

creation of a national database to store testing results for 

all agencies (federal, state, and tribal) and organizations. 

In response, the Wildlife Disease Information Node of the 

National Biological Information Infrastructure created the 

HPAI Early Detection Data System (HEDDS) to manage 

data collected under the Wild Bird Surveillance Plan. 

Current information on the Plan, including the number 

of birds sampled and tested, the geographic distribution 

of samples collected, and information on low-pathogenic 

H5N1 virus isolates detected, is available at: http://

wildlifedisease.nbii.gov/ai/.

U.S. Department of the Interior’s Role

The Department of Interior’s role in the Wild Bird 

Surveillance Plan, an essential part of the National 

Strategy for Pandemic Influenza, is to sample and 

test high-priority migratory bird species for HPAI. To 

accomplish this, the U.S. Geological Survey (USGS) and 

the U.S. Fish and Wildlife Service focused on the three 

strategies listed below and targeted wild bird species in 

North America that have the highest risk of being exposed 

to HPAI. The Plan included many species that migrate 

As of October 2007, more than 190,000 wild 

birds in the U.S. have been tested for influenza 

viruses under the Wild Bird Surveillance Plan. 

Highly pathogenic avian influenza has not 

been detected in wild birds anywhere in North 

America. Surveillance results from testing 

across the U.S. are reported in an online data 

repository (HEDDS). To view the five sampling 

categories and 

see how those 

numbers break 

down by state, 

go to http://

wildlifedisease.

nbii.gov/ai/.

Photo by Don Becker, USGS.

Testing samples for avian influenza 

inside a biological safety cabinet.
directly between Asia and North America. The USGS 

National Wildlife Health Center performs laboratory 

testing of birds from DOI lands and is the lead agency for 

investigating wild bird mortality events throughout the 

United States.

Wild Bird Mortality Investigations

Sick and dead wild birds have frequently been the 

first indication of the introduction of HPAI H5N1. As 

of October 2007, more than 3,000 birds that were found 

dead have been tested for avian influenza. Between April 

2006 and October 2007, USGS investigated a total of 172 

separate events of wild bird mortality and disease from 

across the United States. Of these, 36 were large-scale 

events where more than 500 birds perished. None of the 

mortality events were found to be caused by HPAI H5N1. 

EXPLANATION

 1 – 1,000 samples

 1,001 – 2,000 samples

 2,001 – 3,000 samples

 3,001 – 4,000 samples

 4,001 – 5,000 samples

 > 5,000 samples

California

8,760

Alaska

31,890

Hawaii

1,778

Oregon

4,894

Washington

6,501

Montana

3,328

Idaho

3,445

Nevada

3,129

Arizona

2,254 New Mexico

2,200

Wyoming

1,560

Utah

3,952 Colorado

3,383

North Dakota

4,488

South Dakota

4,031

Nebraska

4,129

Kansas

3,307

Oklahoma

2,838

Texas

4,099

Minnesota

4,356

Iowa

2,549

Missouri

2,786

Louisiana

4,283

Arkansas

2,703

Mississippi

2,549

Alabama

2,534

Wisconsin

3,586

Illinois

3,281

Michigan

3,547

Indiana

2,467

Ohio

2,497

Pennsylvania

2,250

New York

3,476

Maine

2,446

Washington, D.C., 8

Delaware 4,959

New Jersey 3,360

Connecticut 2,887

Rhode Island 2,383

Massachusetts 2,377

New Hampshire 2,535

Vermont

2,494

Kentucky

2,374

Tennessee

2,406

Florida

2,990

Georgia

2669

South 

Carolina

2,659

North Carolina

2,592

Virginia

3,099

W. Va

1,827

Number of samples reported by state to the HPAI Early Detection Database System, April 2006–October 2007. 

Sampling strategy results from Interagency Wild Bird Surveillance Plan, April 2006–

October 2007 (reported in HEDDS).

Sampling strategy Number of birds 

tested HPAI H5N1 found

Wild Bird Mortality Investigations 3,181 No

Live Bird Surveillance 63,371 No

Hunter-Harvested Bird Surveillance 68,191 No

Sentinel Birds 579 No

Environmental Sample Testing 53,394 No

Total 193,716

U.S. Fish and Wildlife Service employees 

collecting a sample from a tundra swan in 

Alaska to test for avian influenza.

Photo by Heather Wilson, USFWS
Northern pintail 

ducks are one of the 

high-priority species 

specified in the Plan 

for avian influenza 

testing.

Photo by Dave Menke, USFWS.

Potential 

pathways of 

avian influenza 

introduction from 

Asia to North 

America.

Live Bird Surveillance

Scientists collected samples from live birds known 

to migrate between Asia, where HPAI H5N1 is known to 

occur, and North America. Samples were also collected 

from species that co-mingle with these intercontinental 

migrants. No highly pathogenic H5N1 viruses were found, 

but normally occurring low pathogenicity viruses were 

found in nearly 2% of the birds examined. Of the samples 

tested to date, a number of H5 avian influenza subtypes 

have been identified. None of these viruses have been 

found to be highly pathogenic H5N1.

Surveillance of Hunter-Harvested Birds

DOI samples were also collected from hunterharvested birds, primarily waterfowl in Alaska and the 

Pacific Flyway. Alaska was chosen for the initial focus 

of surveillance because it is a major crossroad for several 

migratory flyways used by species that travel directly to 

Alaska from Southeast Asia or the Australasian Flyway. 

Spring hunting in Alaska is an important aspect of 

subsistence for many Native Alaskans and represents 

some of the earliest opportunities to test birds recently 

returning to North America. Samples from approximately 

6,700 wild birds taken by participating Native Alaskan 

subsistence hunters were tested as part of the Wild Bird 

Surveillance Plan. The regular autumn waterfowl hunt 

represented another opportunity to test additional birds for 

HPAI in Alaska and other states. 

While no highly pathogenic avian influenza has been detected in the U.S., several hundred 

low pathogenic avian influenza viruses have been isolated during the surveillance program, as 

expected. These viruses are commonly found in wild birds and their detection provides scientists 

with data that greatly improves our understanding of the role that wild birds play in the global 

movement of avian influenza.

Natural

avian influenza

cycle

Pandemic

disease

cycle

Waterfowl Mammals

(Primarily swine)

Shorebirds

Domestic

birds

Humans

Global cycle of avian 

influenza viruses in animals.
Migration flyways of the world. Note that Alaska is a major crossroads for several flyways.

Federal Web Sites with Avian Influenza Information

Pandemic Flu, http://www.pandemicflu.gov/

U.S. Department of Interior, http://www.doi.gov/issues/avianflu.html

USGS National Wildlife Health Center, http://www.nwhc.usgs.gov/disease_information/avian_influenza/index.jsp

USGS Alaska Science Center, http://alaska.usgs.gov/science/biology/avian_influenza/index.html

U.S. Fish and Wildlife Service, http://www.fws.gov/home/avianflu/

U.S. Department of Agriculture, http://www.usda.gov/wps/portal/!ut/p/_s.7_0_A/7_0_1OB?navid=AVIAN_

INFLUENZA&navtype=SU

For more information, contact 

Paul Slota 

USGS National Wildlife Health Center 

6006 Schroeder Road

Madison, WI 53711 

Tel. 608-270-2400

http://www.nwhc.usgs.gov

Page 1 top, left and right photos by Robert Gill, USGS Alaska Science Center; 

center photo by Don Becker, USGS. 

For a summary of the Wild Bird Surveillance Plan, 

please see USGS Fact Sheet 2009-3025 (http://

www.nwhc.usgs.gov/publications/fact_sheets/

pdfs/ai/AIFEB06.pdf). A link to the plan is available 

at the USGS National Wildlife Health Center’s 

Web site: http://www.nwhc.usgs.gov/publications/

other/Final_Wild_Bird_Strategic_Plan_0322.pdf