The Avian Flu that is decimating birds in the wild, domesticated chickens, geese – now jumping to mammals –

A male Northern Pintail gliding downstream along the South Platte River, in Thornton, Colorado. February 11, 2023. (R. Prince photo)
Although many of the people who I meet and greet regularly are obviously to the fact – other than they know the price of eggs as soared – the world, including the USA is in the midst of another epidemic. I am not talking about COVID-19 this time. It – the global Avian Flu epidemic – remains serious, disturbing. as poultry are slaughtered nationwide. According to the Wall Street Journal, it is the worst avian-influenza outbreak in U.S. history. It continues to decimate poultry flocks across the Midwest and Colorado, frustrating efforts to keep the virus from affecting the nation’s egg prices and supply. According to a January 10, 2023 NPR in Northern Colorado report, the state has euthanized some 6.4 million poultry in an effort to stem the tide of the epidemic.
And now there are indications that the virus involved, H5N1, is jumping from bird species to mammals. A recent NBC news special noted that it has spread to minks, sea lions and other mammals. “Hundreds of wild sea lions in South America, a farm of minks in Europe, and more than 58 million poultry birds have died.” That last figure is a worldwide casualty number. The sheer amount of H5N1 circulating has heightened the risk the virus could spill over into other species, develop the ability to transmit among people and become a pandemic.
So, dangerous stuff and plenty of it “out there” including here in Colorado

Norther Shoveler coming in for a landing on the S. Platte near where dead ducks have been seen. (R. Prince photo)
When I first began to become cognisant of the flu epidemic ravaging both domestic poultry, birds in the wild, I was walking along South Platte River Trail, ten miles or so north of Denver. Within a few days, walking along the trail to the confluence of Clear Creek and the South Platte, I noticed first a dead duck, I believe a mallard floating downstream (in the northeasterly flow of the river there), its yellow web feet up in the air. In a decade of bird photography, that was a first. A few days later, a mile or so beyond this first spot, there was another dead bird, this time a male Northern Shoveler, its body sitting right smack in the middle of the path. I examined it for a few moments without touching it and walked on. About ten minutes later returning along the path I saw a male Northern Harrier hawk pecking away at the body, annoyed that I was interrupting its late lunch by simply walking back by the spot. It flew away. When I was about fifty feet beyond the corpse, I turned, and sure enough the harrier was back pecking away at the body.
Was the Harrier infected from its meal? I guess we’ll never know but reports of birds dying abound. In Colorado Boulder County seems to have the highest number of fatalities but they are happening all over the state and, of course, beyond. According to the Colorado Department of Agriculture website,
- “Since approximately November 20, more than 2000 snow geese near the towns of Brush and Fort Morgan in Morgan County, have died due to an outbreak of Highly Pathogenic Avian Influenza.
- An additional detection in snow geese in Prowers County was confirmed on December 8, 2022. Boulden, Aspent, Montrose and Durango are the worst areas in the state with the state’s northeast (along the tributaries of the S. Platte) and the far southwest also showing high numbers of dead birds.
- A list of dead birds tested from January 18 through February 14, 2023 includes Great horned owls, Swainson and Red tail hawks, Canada geese, crows, just to give a sense of the most prominent victims.
- A January 12, 2023 Lyons Reporter article reported the deaths of geese in Lyons. near the McConnell Ponds. Colorado Parks and Wildlife (CPW) has confirmed that Lyons could be experiencing an outbreak of Highly Pathogenic Avian Influenza (HPAI). The article went on to name the species of some of the victims: “Raptors and owls seem to be hit hard. CPW has told the Town that it will likely impact the following wildlife species: swans, gulls, geese, grebes, pelicans, raptors, vultures, cranes, and some species of ducks
- A January 20, 2023 article in the Boulder Daily Camera reported finding dead geese on campus, including 17 at the pond at 28th Street and Colorado Avenue, and two at the pond near the Kittredge residence halls. The same article noted dead geese in ponds along Longmont including Loomiller Park.

Ducks along the S. Platte just northeast of Denver
This epidemic reaches far beyond Colorado.
According to the Center for Disease Control, close to 60 million birds in the USA have died of Avian Flu – also called Highly Pathogenic Avian Influenza (HPAI) having contracted the H5N1 virus. It has affected 47 states with 762 outbreaks. Victims include wild aquatic birds, commercial poultry and backyard or hobbyist flocks. According to the CDC, the casualties are from January, 2022 to February 15, 2023 (that is to say yesterday). CDC has been comparing the properties of current H5N1 bird flu viruses to past H5N1 bird flu viruses and has found that current H5N1 bird flu viruses detected in the U.S. during late 2021 and 2022 are different from earlier H5N1 bird flu viruses.
As the highly infectious virus continues to spread, the United States Department of Agriculture Animal and Plant Health Inspection Service announced (on January 18, 2023) that it intends to prepare an environmental impact statement for HPAI control in the USA although a date for its announcement was not given.
Where did this Avian Flu virus originate? Was it a natural mutation that started somewhere among the avian populations? Or somewhere else? Stay tuned…

Northern Pintails floating downstream on the S. Platte