Thousands of migratory birds have died inexplicably in the southwestern US, which ornithologists have described as a national tragedy likely to be related to the climate crisis.
Flycatcher, swallow and wallburger species are among the “falling out of the sky” as part of a mass die-off in New Mexico, Colorado, Texas, Arizona and Nebraska in the north, with growing concerns already hundreds of thousands dead Can. Said, Martha Desmond, is a professor in the Department of Biology at New Mexico State University (NMSU). Many carcasses contain the remaining fat reserves or muscle mass, some of which appear to be plaguing the middle flight of the ground.
“I collected more than a dozen in front of my house just a two-mile stretch,” Desmond said. “To see this and to pick up these bodies and realize how widespread it is, is personally devastating. The death of many individuals and species is a national tragedy to watch. “
Long-distance migrants flying south from the tundra landscape in Alaska and Canada pass through the southwest of the Americas to reach the wintering grounds in Central and South America. During this stay it is important that they take off every few days to refuel before continuing their journey.
Historic wildlife in the US western states may mean they have to keep their migration away from resource-rich coastal areas and travel inland to the Chihuahuan Desert, where food and water are scarce, essentially meaning they Was starved to death. “They are really just wings and bones,” wrote Allison Salas, a graduate student at NMSU who was collecting the bodies Twitter thread About to die. “Almost as if they have flown until they can just fly.”
America’s southwestern states have experienced extremely dry conditions – believed to be related to the climate crisis – meaning fewer insects may be the main food source for migrating birds. Locally cold snape between 9 to 10 September can also be bad for birds.
Any of these weather events may have induced the birds to begin their migration early, not having created enough fat reserves. Another theory is that the smoke of wildlife can spoil their lungs. “It can be a combination of things. It could be something that is still completely unknown to us, ”said Salas.
“The fact that we are finding hundreds of these birds dying is just one type of falling out of the sky. It is dangerous that the amount of dead bodies we have found is really freezing to me.”
The first deaths were reported on 20 August at the White Sands Missile Range in New Mexico. Initially, the events were considered unrelated, but thanks to online forums, ornithologists noticed that they were occurring throughout the region. Resident bird species such as curved-badge thresher, great-tailed grackle and white-winged pigeon are not affected.
Reports suggest that some birds continue to display unusual behavior before they die – dull, inaccessible and gathering in groups. Desmond said that the species usually appears to be resting in trees and bushes, insects are seen on the ground.
Large avian mortality rates during migration are rare and some have been as large as this one. Records – which go back to the 1800s – suggest that these events are always associated with extreme weather events such as temperature drop, snowstorm or hail. The largest event on record in the region occurred in Minnesota and Iowa in March 1904, killing 1.5 million birds.
Climate crises are also changing the tundra landscape, where many of these birds breed, while the destruction of rainforests in Central and South America is damaging their wintering habitats. Since 1970, three billion birds have been lost in the US and Canada. People who die extensively in this way can have an impact on populations of both common and susceptible species. Salas said: “We are going to come at them all the way … If we do nothing to protect their habitat we will lose a large number of populations of many species.”
The carcasses are being sent to the US Fish and Wildlife Service Forensic Laboratory in Wisconsin for testing and placed at the National Wildlife Health Center for testing, which is expected to take at least two weeks. Scientists are urging the people of the field to look at the birds of the dead on the website of Citizen Science.
Tristan Bickford, director of communications at the New Mexico Department of Game and Fish, said it is likely that the climate crisis has affected migration. “Until we get the actual report from the National Wildlife Health Center, we cannot say what is happening or what is not happening,” he said.