“I thought to myself, ‘Wait, I’ve never seen this many dead animals in one place in my life,’” Mr. Fisher said. He said a graduate student from the University of New
Andrew Farnsworth, a senior research associate at the Cornell Lab of Ornithology, noted that the die-off began before the sharp drop in temperatures in New Mexico last week. He added that the deaths amounted to “clearly a major, major event” in the broader problem of migratory birds being killed, often by cats or by crashing into man-made structures.
“It’s different this year than other years,” Dr. Farnsworth said, adding that he believed that the wildfires could be a potential trigger for the bird deaths. “We’ve had plenty of hot summers but very few that have had these huge-scale fires combined with heat combined with drought.”
Dr. Farnsworth said the particulate matter or toxic compounds from smoke could be a prime factor. Pointing to migration patterns, he said that researchers could find similar reports of dead birds even into northern Mexico and “all the way up the Rockies.”
Many different types of birds have been found dead in New Mexico in recent weeks, including warblers, swallows and flycatchers. Tristanna Bickford, a spokeswoman for the New Mexico Department of Game and Fish, said it would take some time before biologists could conclusively determine what was causing the die-off.
Ms. Bickford said New Mexico officials had provided specimens of the dead birds to the National Wildlife Health Center in Wisconsin for examination. She said it could potentially take months to diagnose the cause if a significant amount of testing was needed.
“This is definitely not a normal thing,” Ms. Bickford said.
In the meantime, Ms. Bickford urged people who come across ailing or dead birds to proceed with caution. She recommended keeping cats indoors to alleviate additional stress on migratory birds and urged people to wear gloves if they collect specimens of dead birds to hand over to game and fish authorities.