Avian influenza is spreading with the spring migration of wild birds, and although federal officials report 665 cases in wild birds in 38 states, those numbers don’t yet include recent confirmations in Wyoming.
This year’s avian influenza outbreak appears to be more severe than those in the past, killing more than 5,200 wild cranes at a migration stopover in northern Israel in December, and affecting domestic bird flocks on a massive scale.
The good news is that this bird flu generally poses a low risk to the public, and there haven’t been any human cases reported in the United States. Avian influenza is rarely transferred to humans, but when it does, cases can be lethal.
The bad news is that the outlook for domestic flocks and a variety of wild birds that contract the virus is glum.
The USDA Animal and Plant Health Inspection Service (APHIS) is the agency tracking avian influenza in both domestic birds and wild bird species, and reports that this year’s highly pathogenic avian influenza (HPAI) virus strains are extremely infectious and often fatal in domestic chickens, with rapid spread from flock to flock. Infected birds shed bird flu virus through their saliva, mucous and feces.
The CDC reports that the number of U.S. domestic poultry affected by the virus since the start of the year stands at more than 28 million, including backyard flocks in Park, Fremont, Johnson, and Sheridan counties in Wyoming. When bird flu is detected in a domestic flock, the entire flock is depopulated by animal health officials. The Wyoming flocks impacted by the virus range in size from about 40 to 100 birds.
As the proverb goes, birds of a feather flock together, and wild bird species that congregate together seem to be the most impacted by avian influenza. Nearly half of all wild bird cases detected in the United States this year are in ducks and geese.
But what is concerning for bird enthusiasts is the rising number of birds of prey that are impacted, with three dozen dead bald eagles detected thus far, from Florida to Maine, and from North Dakota to Georgia. Avian predators like eagles, hawks and owls that hunt or scavenge infected birds may then become ill with the deadly virus. There have been more than 30 fatal cases confirmed in black vultures, another scavenger species.
Other cases detected in wild birds of prey include eight cases in hawks, including five red-tailed, two Cooper’s, and one red-shouldered hawk. Another 10 cases were in owls, including five snowy owls and five great horned owls, with detections reported mostly across northern tier of the country.
Not yet included in the federal numbers are new cases reported last week by the Wyoming Game & Fish Department. Two great horned owls from Park County, one Canadian goose from Bighorn County, and two Canadian geese from Fremont County all tested positive for the highly pathogenic avian influenza. Since then, Wyoming has also detected the virus in wild turkeys and a black-billed magpie.
The scope of wild bird species affected by HPAI is growing, and now ranges from pheasants to trumpeter swans. Recent detections of the virus in game birds such as wild turkeys and pheasants are especially concerning to sage grouse advocates.
The federal plan for monitoring wild bird infections noted “it is reasonable to assume that many of our wild gallinaceous birds such as turkeys, pheasants and grouse may very well be susceptible to avian influenza and suffer notable mortality.”
Greater sage grouse are currently congregating on their breeding grounds, called leks. According to WG&F, breeding activity usually peaks in late March and early April, so we are past the point that most grouse will be in attendance. By this time of year, most of the breeding is complete, so it’s mostly male grouse that are still present on the leks.
WG&F notes that wild birds can carry HPAI and not appear sick. Some birds might exhibit signs of neurological impairment or may be found dead with no apparent cause. Noting that HPAI is zoonotic disease that can infect humans, WG&F requests that anyone who finds a cluster of dead birds should notify the nearest WG&F office, but do not touch or handle sick or dead birds or allow your pets to come into contact with these birds.
Cat Urbigkit is an author and rancher who lives on the range in Sublette County, Wyoming. Her column, Range Writing, appears weekly in Cowboy State Daily.
