LAS CRUCES – Biologists from New Mexico State University and White Sands Missile Range examined nearly 300 dead migratory birds Saturday at Knox Hall on the university’s main campus.
Over the past few weeks, various species of migratory birds are dying in “unprecedented” numbers of unknown causes, reported Martha Desmond, a professor at NMSU’s Department of Fish, Wildlife and Conservation Ecology.
“It is terribly frightening,” Desmond said. “We’ve never seen anything like this. … We’re losing probably hundreds of thousands, if not millions, of migratory birds.”
In August, large numbers of birds were found dead at White Sands Missile Range and at White Sands National Park in what was thought to be an isolated incident, Desmond said.
After that, however, came reports of birds behaving strangely and dying in numerous locations in Doña Ana County, Jemez Pueblo, Roswell, Socorro and other locations statewide.
The affected birds have included warblers, sparrows, swallows, blackbirds, flycatchers, and the Western wood pewee.
“A number of these species are already in trouble,” Desmond said. “They are already experiencing huge population declines, and then to have a traumatic event like this is – it’s devastating.”
On Saturday, Desmond was joined by Trish Cutler, a wildlife biologist at WSMR, and two NMSU students for an initial evaluation of the carcasses.
Desmond said her team also began catching and evaluating living specimens Friday as residents reported finding birds behaving strangely and gathering in large groups before dying.
“People have been reporting that the birds look sleepy … they’re just really lethargic,” Cutler said. “One thing we’re not seeing is our resident birds mixed in with these dead birds. We have resident birds that live here, some of them migrate and some of them don’t, but we’re not getting birds like roadrunners or quail or doves.”
On the other hand, numerous migratory species are dying rapidly and it is not immediately clear why, although the cause appears to be recent. Desmond said the birds had moulted, replacing their feathers in preparation for their flight south, “and you have to be healthy to do that; but somewhere after that, as they initiated their migratory route, they got in trouble.”
The biologists guessed the cause might involve the wildfires ravaging the western U.S. and dry conditions in New Mexico.
“They may have been pushed out before they were ready to migrate,” Desmond said. “They have to put on a certain amount of fat for them to be able to survive the migration. These birds migrate at night and they get up in the jet stream, and they might migrate for three nights in succession, they’ll come down and they’ll feed like crazy, put on more fat and go again.”
The biologists noted that the majority of the dying birds are insectivores, but that seed eaters were sickening and dying as well.
The birds will be sent to the U.S. Fish and Wildlife Service Forensics Laboratory in Ashland, Oregon, for further analysis. Desmond said it could be weeks before results come back, and the findings could bear serious ecological implications.
“Over 3 billion birds have died since 1970. Insect populations are crashing, and this is just an unprecedented mortality,” she said. “Climate change is affecting the abundance of insects, it’s affecting the volatility of the fires, and the scary thing is this is may be an indication of the future.”