MARYSVILLE — Snohomish Health District officials are now collecting mosquitoes and some dead birds to test for presence of the West Nile virus.

According to information provided by the public health agency, fewer dollars for West Nile surveillance required the group to begin specimen collection a month later than in previous years. The health district selected 40 mosquito trapping sites in Marysville, Lake Stevens, Snohomish and unincorporated Snohomish County, spots proven in the past to yield the species of mosquitoes that most commonly carry the virus.

In addition to the usual surveillance work, the health district is working with the Washington Department of Ecology to trap mosquitoes near an undisclosed tire clean-up site.

If you find a dead bird that didn’t die from some obvious injury, note the location and report it by calling the health district at 425-339-8720. Using safe handling procedures, package the bird and, if possible, bring it to 3020 Rucker Ave., Suite 104, Everett.

The health district will accept dead crows, ravens and blue jays for testing if the birds show no evidence of death due to common aviary hazards such as power line electrocutions, hitting windows or vehicles, other bird-only diseases, fights with other birds or animals, poisoning, shooting or, in the case of young birds, abandonment.

The health district received negative results on 49 birds tested in 2007.

Safe handling of dead birds includes using gloves or a shovel to place the bird in a sealable plastic bag. Use two bags to “double-wrap” the bird. If the bird cannot be tested, double wrap it and place in the trash.

Mosquito bites transfer the West Nile virus from infected birds to other animals and humans. According to the health agency, the risks to humans increases in late summer as some birds start to migrate, leaving hungry, infected mosquitoes behind. No people in Washington contracted West Nile last year, but eight horses, one bird and one dog tested positive for the virus.