Species-Specific Management (SSM)

Crows, Jays, and Ravens

Increasing a population:

The crow, raven, and blue jay benefit the environment in many ways. Crows and ravens are scavengers and rid the environment of carrion. Also, they control a variety of crop insects that are considered pests by farmers, such as cutworms. Blue jays are prized for their aesthetic value and for dispersing acorn, walnut, and hickory tree seeds in the southern Appalachian forest. Migrating jays are a major food source for migrating hawks.

1. In general, crows, ravens, and jays tend to prefer habitats for nesting that have these species of trees: sycamore, chestnut, holly, beech, sweetgum, sassafras, oak, and cedars. These trees must have a diameter greater than 13 inches and be around 20 to 50 feet high.
2. Most crows are omnivorous, and eat eggs, carrion, insects, and corn in great quantities. By planting monocultures of corn or wheat, crow numbers can be increased. Blue jays can be increased by increasing oak trees and beech, since they prefer hard mast (nuts) for the winter.
3. In plowed fields, ravens, American crows, and fish crows eat grubs, cutworms, ants, and grasshoppers, which are detrimental to farmers' crops. Therefore, farmers may be pleased about the benefits these birds may provide.
4. An increase in heron rookeries, hawks, and owls would increase the nesting sites of crows. Crows use old nests.
5. More strict laws prohibiting hunting or creating a shorter hunting period can be passed and enforced.

Decreasing a population:

The primary reason that a bird population would need to be decreased is because the population is viewed as a nuisance or are disease reservoirs. These include crows eating farmers' corn in the fall months, ravens killing young livestock and poultry, and jays destroying other more valued birds' eggs such as those of the cardinal.

Temporary ways

1. Crows and ravens will fly from loud noises such as using an exploder or firing a gun. Jays are known to be less frightened by these noises. Other noises than can be used are: noise cannons; rockets; or recorded distress calls. Farmers can use this technique especially during the harvesting months (August to September).
2. Increase populations of redwing blackbirds, kingbirds, terns, or yellow-headed blackbirds. These birds chase crow species.
3. Farmers and urban gardeners can use scarecrows or strong reflective tapes inside their fields or gardens in order to keep crows and ravens out of their fields during the harvesting months (August to September).

   More permanent ways

4. Increasing populations of red-shouldered hawks, red-tailed hawks, goshawks, sharp-shinned hawks, Coopers hawk, or mammals such as red or gray foxes. These animals kill crows species and jays.
5. In the past, bombing roosts with dynamite while the birds were nesting was considered a means of control for American crows and ravens. Many birds have been killed this way.
6. Increase participation in hunting season of crows. These hunting seasons should be from December to February and should not be more than 125 days. Also setting up owl decoys attracts crows.
7. With experts, consider using repellents such as Avitrol or Tergitol applied to roosting birds during winter when conditions are wet and cold, or toxicants.
8. Traps include the "Australian Crow Trap" baited with food and live crows, and rocket or cannon nets set up near problem areas. These are baited with corn. Either release the birds far away from the area (which will probably not work), or kill the birds humanely.
9. Destroy roosting and nesting sites by burning the area or cutting the trees.
10. Reduce the number of road-kills or have them disposed of regularly by highway crews. Also, set up avoidance practices at landfills, garbage bins, and slaughter houses to deter crows and ravens from looking for carrion and trash.
11. Monitor and report the changes and costs per unit change resulting from management.
12. Serious efforts to estimate growth of problems and to take action now to reduce them seem reasonable.

See the note on the related West Nile disease below.

Student author unknown (1992), Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061

Submitted by Robert H. Giles, Jr.

From: Michael Samuel

Wildlife Health Alert #99-04

To: Natural Resource/Conservation Managers
From: Director, USGS National Wildlife Health Center (Bob McLean)
Title: New Virus Isolated from Crows in New York City

On September 24,1999, the Centers for Disease Control (CDC) announced the isolation and identification of the West Nile virus from birds collected in New York City. The West Nile (WN) virus is an arthropod-borne virus closely related to St. Louis encephalitis (SLE) virus, a known virus infection of birds in the United States which occasionally causes human cases and epidemics. The West Nile virus has never been reported in the United States or any area of the Western Hemisphere prior to this isolation. West Nile virus generally causes a milder disease in humans than SLE virus; however it can cause human fatalities and has been linked to the deaths of three people during the concurrent human encephalitis outbreak in New York City. Birds are the natural hosts for these viruses and both viruses are transmitted from birds to other animals, including humans, through the bite of mosquitoes. The virus is not directly transmitted between humans and is not known to be transmitted from birds to humans or to other animals without the arthropod vector.

American crows appear to be especially sensitive to this disease. The USGS National Wildlife Health Center and CDC request your cooperation in a joint national surveillance effort to document mortality in crows. We are interested in receiving reports of sick or dead crows, particularly in the New York area and the states along the Atlantic seaboard. There is ongoing mortality of American and fish crows, blue jays, and several other bird species in New York City and the southern New York counties of Westchester, Rockland, Sullivan, Nassau and Suffolk; Fairfield County in Connecticut; and Bergen, Essex, Union, Middlesex and Monmouth Counties in New Jersey. Specimens from suspect crows collected during this surveillance will be examined by USGS at the National Wildlife Health Center and tested for the presence of WN virus. Selected specimens from probable WN virus positive crows submitted from new locations will be shipped to CDC for confirmation.

Concurrently, USGS and CDC will be collaborating with Dr. Ward Stone (New York Department of Environmental Conservation), New York City and New York State Public Health officials, and the U.S. Fish and Wildlife Service to conduct field investigations in the New York area. Researchers will attempt to determine the wildlife species involved, the geographic and temporal distribution of the new virus in bird populations, and where the virus may be expanding beyond the currently reported sites. There is concern that if migratory birds are infected, the virus will move farther south during fall migration.

For further information and to report sick or dead crows or other unusual bird mortality, please contact USGS, Wildlife Disease Specialists Drs. Linda Glaser (608-270-2446, linda_glaser@ usgs.gov) or Kathryn Converse (608-270-2445, kathy_converse@usgs.gov).

This Web site is maintained by R. H. Giles, Jr.
Last revision July 17, 2002.