Pair of wildlife diseases detected in Montana birds

Multiple groups of up to 70 wild doves were found dead near Belgrade, Montana, in the final two months of 2023. The culprit: pigeon paramyxovirus, often referred to as PPMV. It’s one of two avian diseases recently recorded in the state, according to Montana Fish, Wildlife and Parks.

FWP responded to reports by residents where groups of doves were found dead, and disease testing revealed positive results for PPMV, FWP’s Morgan Jacobsen told Mountain Journal. PPMV typically impacts doves and pigeons alone, and the strain detected in Montana rarely infects mammals, according to a January 8 FWP press release. Additionally, there have been no recorded cases of the strain causing diseases in U.S. poultry.

“Monitoring these diseases helps keep track of prevalence and distribution,” Jacobsen said, explaining that FWP monitors for a variety of wildlife diseases year round, including chronic wasting disease in ungulates. “[Monitoring] can help us better understand how wildlife can be affected over time and space.”

The other avian disease found in the state since 2022—highly pathogenic avian influenza, or HPAI—is extremely infectious and fatal to poultry and some species of wild birds. Although cases are currently low in Montana, the spread is cyclical and often spikes during spring and fall migration, Jacobsen explained.

“With avian flu, there are fairly broad impacts because it affects multiple species,” Jacobsen said. “In terms of population-level impacts, I think the long-term prognosis is unclear. We haven’t seen any significant die-offs, but that’s something that we’re watching closely when we get these surges of cases.”

Among the impacted species are various iconic wild birds of the region, including the bald eagle, great horned owl, great blue heron and trumpeter swan. Three grizzly bears, a handful of skunks and a single mountain lion are among the mammals that have been infected in the state with HPAI since it was first documented in 2022, according to a Dec. 11 FWP dataset.

The diseases are not isolated to Montana and many other U.S. states are experiencing the spread of both HPAI and PPMV. Jacobsen said Montana is “in the loop” with monitoring and research efforts occurring in other areas of the country to help guide state action.

The risk of transmission to humans for both diseases is low, however FWP recommends taking precautions when handling birds that may appear to be sick or have already died. Hunters are advised to avoid harvesting birds that appear ill in order to avoid unnecessary risk.

“If a bird has trouble moving, that's an indicator that the bird may be sick or injured,” Jacobsen said, noting that lack of mobility and lethargy are the telltale signs of illness. While transmission probability to pets is low, Jacobsen said owners can protect their pets by limiting their exposure to both wild birds and domestic poultry.

State officials will determine where disease testing is warranted to continue monitoring the spread of HPAI and PPMV. Jacobsen encouraged Montanans to call their local FWP office if they come across sick or dead birds, and to notify the Montana Department of Livestock at (406) 444-2976 if they suspect an outbreak of HPAI in domestic animals or poultry.