More on Sudden Bird Death

Maybe not fires, but abrupt cold:

Last week, the Rocky Mountain states experienced a strong storm that brought with it snow, near hurricane force winds, and unseasonable record-breaking cold temperatures. In Albuquerque on September 8, it was sunny and a record-high 96ºF. The next afternoon, a severe windstorm tore through the region. The Albuquerque airport measured windspeed of over 70 mph, and temperatures plummeted to historic lows. Albuquerque broke a 100-year record low temperature when the mercury dropped to 40ºF. While snowfall was heaviest in the northern Rockies from Montana to Colorado, New Mexico received several inches of heavy, wet snow as far south as the Sandia Mountains east of Albuquerque.

 

My colleagues and I spent the morning of Thursday 10 September picking up dead birds in the Sandias. We found several dead Empidonax flycatchers of three species, a Vesper Sparrow, and a Townsend’s Warbler. Some birds were wet from the overnight snow, but others were completely dry, huddled in the corners of buildings. A Dusky Flycatcher sat dazed in the parking lot.

 

We first thought little of it: mortality is expected for migratory birds, and we didn’t find more than a handful of carcasses. But social media told a grimmer story that night. We read reports of widespread mortalities across the state: dead swallows along a bike path in Albuquerque, a half-dozen Empidonax flycatchers and swallows in one park in Clovis, and a local news report of 300 carcasses recovered by researchers from New Mexico State University and nearby White Sands Missile Range. It was soon apparent that a significant mortality event had occurred.

 

But one video on Twitter recorded by local journalist Austin Fisher stood out to me: several dozen swallows dead in an arroyo in Velarde, approximately 40 miles north of Santa Fe. It was only when I reached out to Austin for the purposes of this report that I realized the video wasn’t taken the week before during the cold snap, but rather the previous night, on 13 September. To see it for myself, fellow ornithology grad student, Nick Vinciguerra, and I drove the hour and a half north that night.