Hundreds of thousands of birds found mysteriously dead in New Mexico were likely killed by a historic cold snap — not raging wildfires, researchers said in a report Wednesday.

“I am no stranger to dead birds but I [have] never seen anything like this,” University of New Mexico Ph.D. student Jenna McCullough, who was involved in the study, told Taosnews.com

An “unprecedented” number of bird carcasses were found in the US Army White Sands Missile Range and other parts of the state two weeks ago, prompting concerns from onlookers, who posted images on social media.

Experts had previously said that the feathered creatures may have been harmed by smoke from the dozens of wildfires tearing through the Western US.

But after conducting tests, UNM researchers say a cold front blowing historically low temperatures down the Rocky Mountains likely killed off insects eaten by the birds, as well as induced hypothermia.

For the study, ornithology Ph.D. students McCullough and Nick Vinciguerra collected 305 carcasses, mostly violet-green swallows, and took them to labs at the UNM’s Museum of Southwestern Biology in Albuquerque.

They found a lack of fat stores and atrophied breast muscles in the birds — signs of dehydration and starvation they say probably killed the birds.

The state Game and Fish Department is still awaiting results from animal autopsies.