Mass avian deaths across New Mexico include birds from the East Mountains and Estancia Valley, likely the result of a cold snap which hit the state last week, bringing freezing temperatures and snow.
After record cold temperatures hit the state, reports of dead birds and birds behaving out of character came in from all over. This reporter witnessed several dozen reports in the area on social media on Wednesday of last week.
The last time the state experienced temperatures as low as freezing this time of year was Sept. 9, 1915.
Bird migration begins anywhere from the end of August to early to mid-September; this week is the peak of bird migration in New Mexico.
Jenna McCullough, a 3rd year PhD student at the Museum of Southwestern Biology at University of New Mexico, said she heard reports “via people in the museum community about bird deaths in the East Mountains.”
She and a colleague went to the Sandia Mountains and collected specimens. McCullough said they found several dead flycatchers from three different species, a Vesper Sparrow and a Townsend’s Warbler.
She said the museum was not part of the investigating team collecting specimens across the state, but is also collecting data related to the bird deaths. After a call, they also went to Velarde and found 305 individual birds of six species of migratory insectivores.
McCullough said they noticed the birds from Velarde were underweight, with no sign of fat, and with muscle atrophy, when compared to others of the same species. “The average is 15 grams, these were much lighter with an average weight 9.5 grams,” she said.
McCullough hypothesizes that bird deaths across the state are likely from lack of insects. She said cold temperatures don’t just affect the birds, but also affect insects, which is the food source for most of the migratory birds that have died.
She said the cold weather can also cause lethargic behavior, and that birds are known to huddle up in caves and crevices together when it’s really cold, sometimes dying in groups.
Migration is one of the most dangerous times in a bird’s life, McCullough said, explaining that they spend a lot of time eating food to store enough fat to travel great distances.
Many birds lose their lives to migration, not only because the journey is arduous but also because of other obstacles including predators, man-made structures and weather systems.
Joan Garth, an East Mountain resident said, “Wednesday morning, I saw at least a dozen dead birds on the ground and we are still finding them.”
Garth works for an alpaca farm in Sandia Park and said swallows nests in the barn every year. She said she has never seen migratory birds die before. Garth has lived in the East Mountains for more than 20 years and has worked at the farm for three years.
Wildland Biologist for Sandia and Mountainair Ranger Districts Amanda Rael said so far no bird death “events” have been reported in this area.
Wildlife biologist James Taulman also reported not seeing anything out of the ordinary in this area.
The first report of large numbers of dead birds in New Mexico was Aug. 20. “There were early reports from southern New Mexico in White Sands and Las Cruces but it’s not [a bigger event] there than anywhere else,” said Jon Hayes, Executive Director of Audubon Southwest.
Hayes said throughout September more reports of dead birds have come in from across the state, including Velarde, Clovis and Albuquerque.
He said the peak in deaths was immediately following the record cold temperatures. Hayes said he hasn’t spoken to anyone in the East Mountain area, but said there were “significant reports taken from the greater Albuquerque area around the river.”
The birds affected so far are primarily migratory birds with insectivore diets. Hayes said they have had reports and collected specimens of swallows, flycatchers, sparrows, warblers, and tanagers.
In the last couple of days Hayes said he was informed about “four flammulated owls that were brought into the wildlife center in Española in poor condition or dead.”
These owls are larger, and also migrate and eat insects. Hayes said those deaths are “alarming because they are not seen very much and the species are already in decline.”
“In northern New Mexico the vast majority of bird deaths occurred after the cold snap,” said Martha Desmond, Professor of Fish and Wildlife Conservation Ecology at New Mexico State University in Las Cruces.
She said, “We don’t see these [reports across the state] as separate events.” After the first reports from White Sands and Las Cruces came in, scientists started collecting samples. Desmond said reports of bird deaths came in from south-central Colorado, Utah, New Mexico, and west Texas.
There is now a team collecting samples and sending them to the N.M. Game and Fish, who will help get them to federal labs for testing in Wisconsin and Oregon. Hayes said over 300 specimens have been submitted.
“Mass avian deaths have been documented in the past and it’s usually associated with weather like hail, snow or wind,” Desmond said, adding, “Migration is a very vulnerable period for birds and there is no question that they die every year.”
She said while the storm resulted in an unusually large number of deaths, that number is a small fraction of the bird population. For example, Desmond said in spite of recent die-offs, “60 million birds took to the skies last night.”
Desmond emphasized that the exact number of deaths across the state is still unknown, and that the exact cause for the deaths is also still unknown.
Desmond said several hypotheses are forming about what could be causing the bird deaths, including that the birds could be in a weakened condition because of the fires in California, Oregon and Washington.
She said birds can be pushed off course during migration or that the fires could have contributed to mortalities.
She pointed out that large-scale fires on the scale of what is happening in the West are unnatural, and said those fires are changing conditions for birds.
Desmond said the labs will administer autopsies to take a look at the lungs as part of the investigation. She said it will likely take a long time to get the results back due to fires in Oregon.
Hayes said there can be many contributing factors when contemplating why birds are dying in larger numbers.
Factors include wildfires, smoke conditions, air conditions, weather systems, temperature changes, droughts, wind speeds, less food production, less plant production, less seed production, and potentially malnourished physical conditions before starting migration.
“To me there is an obvious correlation between climate change which contributes to all of these [conditions] and the death of the birds,” Hayes said. “Issues and problems with wildlife and their habitat will only get worse if we don’t do something now about climate change.”
Hayes said anyone can submit samples to N.M. Game and Fish.
Game and Fish sent out a press release saying they are interested in the observations and photos of the public to aid in the tracking of avian mortality across the state through an app called inaturalist.
For more information about this project for collecting bird data, visit inaturalist.org/projects/southwest-avian-mortality-project to download the app and get involved, or go to their website at wildlife.state.nm.us.
For more information about the Audubon Society, visit nmaudubon.org.