This story has been updated March 30, 2023
Text and photos by Peter Vankevich
With the official arrival of spring, it appears a viral danger to birds has temporarily abated.
Sightings in early winter of sick and dying birds on the Outer Banks and islands in the Pamlico Sound raised alarms of a major outbreak of highly pathogenic avian influenza (HPAI), also known as the avian flu and H5N1.
On Ocracoke’s South Point, in December, approximately 200 dead Double-crested Cormorants and some other species littered the beach.
Many other locations had high avian mortalities.
“We are seeing hundreds of dead and dying cormorants at the large winter roost sites at the inlets of Cape Lookout National Seashore,” said John Altman, its supervisory biologist, earlier this year.
Several dead birds on the dredge spoil known as Big Foot Island, which is a few miles from Ocracoke village in the Pamlico Sound, were sent to the Southeastern Cooperative Wildlife Disease Study (SCWDS) and the National Veterinary Services Laboratory (NVSL).
The lab results were confirmed-positive for HPAI.
In this region, the Double-crested Cormorant was the species most impacted. Gulls feeding on the carcasses were also infected, which accounted for their being seen next to dead birds on the beach. State-wide, Black Vultures have also suffered high mortalities.
Four dead birds found in the Cape Hatteras National Seashore were sent for testing: three Common Loons from Hatteras Island and one Double-crested Cormorant from Ocracoke.
“Avian influenza virus was not detected in any of the loons,” said Amy R. Thompson, Ocracoke’s biological science technician.
It was, however, detected in the cormorant carcass and a sample was forwarded to the NVSL for confirmation, which confirmed it was positive.
“HPAI infection from scavenging gulls was initially a concern of ours, but, thankfully, we have not observed the same level of die-offs or abnormal behaviors in gulls as we did with the cormorants,” she said.
Since that December outbreak, far fewer carcasses have been seen on Ocracoke.
There are always a certain number of dead birds on the beach in winter.
Beach walkers noted in mid-February several dead Razorbills — 14 counted in one day along a 13 mile stretch.
Some of these cold water denizens, the closest living relative of the extinct Great Auk, stray into North Carolina in winter and the number of mortalities seen this winter, although a bit high, is not that unusual.
Several razorbills were sent for testing last month, according to Sarah Van de Berg, wildlife health biologist for the North Carolina Wildlife Resource Commission. “I don’t have results to share but the belief is typical causes for mortality, not HPAI. If it was positive for H5 AIV, we would have heard by now. Prelim AIV results come back with a week or two at most, if they’re positive,” she said.
One cause for mortality for this species is starvation.
Another unusually high mortality is taking place at Mattamuskeet National Wildlife Refuge, which has reported this month seeing dead or sickly Tundra Swans. Two from the refuge were recently submitted to the National Wildlife Health Center for necropsy (autopsy for animals). The birds were also tested for HPAI and those results were negative.
However, the USGS NWHC confirmed lead poisoning in the swans, according to Van de Berg. Lead poisoning has been confirmed in previous years.
Prior to the 1991 nationwide ban, lead shot was used extensively for waterfowl hunting. It is possible that the resulting lead shot in the environment is the cause for the mortality in the swans this year.
The regional HPAI outbreak appeared to have peaked in December and has since diminished.
“We’re still seeing the occasional confirmation of HPAI in raptors, but overall, reports of mortalities due to this virus have slowed down dramatically across the state since January,” Van de Berg said. “While we’ll likely see this virus reoccur in the future, for now, HPAI confirmations have taken a backseat to more typical causes of seasonal mortality in our bird populations.”
HPAI transmissions from domestic fowl to wild birds are having disastrous impacts throughout the world.
In addition to all states except Hawaii, HPAI has also been detected in several Latin American countries. Canada has had outbreaks in all provinces and territories.
This is the largest outbreak in European history, according to the European Food Safety Authority with detections in wild birds in 37 of the 45 European countries. In northern Scotland, thousands of Great Skuas and Northern Gannets have succumbed to the virus in the past two years.
Although officials believe the disease currently poses little risk to human beings, people are warned not to touch distressed birds since contact could cause transmission to other animals.
Some transmissions to several mammal species primarily in northern states have been detected.
The presence of HPAI over the past year has caused the euthanization of approximately 58 million U.S. birds, making it the worst outbreak in national history — resulting in higher prices for chicken, turkey and especially eggs.