Flycatchers, swallows, and warblers are among the species “falling out of the sky” as part of a mass die-off across New Mexico, Colorado, Texas, Arizona and farther north into Nebraska. According to Martha Desmond, a professor in the biology department at New Mexico State University many carcasses have little remaining fat reserves or muscle mass, with some appearing to have nose-dived into the ground mid-flight.
“I collected over a dozen in just a two-mile stretch in front of my house,” said Desmond. “To see this and to be picking up these carcasses and realising how widespread this is, is personally devastating. To see this many individuals and species dying is a national tragedy.”
A possible reason? The deadly wildfires out West. Birds migrating from Alaska and Canada have had to reroute their away from resource-rich coastal areas and move inland over the Chihuahuan desert, where food and water are scarce, meaning they likely starved to death.
“They’re literally just feathers and bones,” Allison Salas, a graduate student at NMSU who has been collecting carcasses, wrote in a Twitter thread about the die-off. “Almost as if they have been flying until they just couldn’t fly any more.”
Reports suggest some birds have been displaying unusual behavior before dying – becoming lethargic, approachable and congregating in groups. Species that normally rest in trees and shrubs have been seen hopping around on the ground looking for insects.
Other possible reasons for the die-off?
The south-western states of the US have experienced extremely dry conditions – believed to be related to the climate crisis – meaning there could be fewer insects, the main food source for migrating birds. A cold snap locally between 9 and 10 September could have also worsened conditions for the birds.
Any of these weather events may have triggered birds to start their migration early, having not built up sufficient fat reserves. Another theory is that the smoke from the wildfires may have damaged their lungs. “It could be a combination of things. It could be something that’s still completely unknown to us,” said Salas.
(via The Guardian; photo: Pixabay)