The Crestone Eagle • October, 2020

Thousands of birds drop dead across the southwest in perplexing die-off

by Zaylah Pearson-Good

With vibrant gold and crimson leaves adorning the mountainside, and a refreshing chill in the air, fall is a glorious season to witness in Crestone. However, this fall has felt a little less sweet due to a dramatic die-off of winged wildlife. Bird corpses are falling like leaves, as biologists report mass fatalities of migratory birds across the southwest and portions of Mexico. Researchers at New Mexico State University (NMSU) estimate that hundreds of thousands of migratory birds have suddenly dropped dead in the last month. Swallows, owls, warblers, flycatchers, hummingbirds, loons and woodpeckers are among some of the many species counted.

While the exact cause of death has yet to be determined, it is clear that all evaluated corpses were extremely undernourished and deficient in fat reserves. NMSU researchers deduced that primary victims were insectivores migrating south. Since migratory species are known to fly thousands of miles across the world, and require abundant energy reserves, a possible explanation for their sudden deaths might be reduced insect availability and feeding period before migration.

The unusual temperature drop/storm felt throughout the Southwest might account for the birds’ emaciation in early September. Though underprepared, some birds may have tried to migrate prematurely, as they sensed the impending storm. For birds that stuck around, frigid temperatures may have killed off large portions of their food supply, or the bird itself. Further perplexing, is that bird die-offs had already been reported in New Mexico back in August– well before the storm hit.

Avian ecologists speculate that the smoke from recent wildfires also contributed to the mortalities. Wildfires are known to induce early migration in birds, contaminate their air supply, and also reduce their visibility and sense of direction. Combined, food shortages, abrupt weather changes, and raging wildfires present as the likely culprit for the mass deaths; however, researchers are still hesitant to point to one cause until further study.

Unfortunately, bird populations across the US have steadily been declining for decades. A study by Cornell Lab of Ornithology concluded that North America hosts 3 billion fewer birds than it did in the 1970s. Many factors play a role in these staggering losses, including habitat loss/fragmentation, decreased insect count, use of pesticides, buildings/infrastructure along migration corridors, and climate change at large.

It is devastating to ponder a world without birds, much like the one imagined in Rachel Carson’s foreboding Silent Spring. Birds serve as important pollinators, seed spreaders, scavengers, and inspire humanity with beautiful song and presence. They are also indicator species, meaning they offer important insight into the health of an ecosystem. Therefore, their decline speaks to humanity’s over-use of chemicals, excessive burning of fossil fuels, urbanization, and overall resistance to face climate change.

Fortunately, there are simple things we can do to support bird populations. According to Andy McGlashen from the Audubon Magazine, “a manicured lawn might look nice, but messy is better for the birds and bugs.” For example, by not removing the withered stocks and pods of perennials, you are saving tiny seeds that provide nourishment to birds in the winter. By not raking leaves, you build soil, fertilize the earth, and offer rich breeding grounds for insects that birds feed on. It is also important to not use pesticides in your yard. This promotes healthy insect populations and keeps harmful chemicals out of the environment. Lastly, promote native plant species that offer critical shelter and food for birds. In Crestone, Big Sagebrush, Blue Grama, Choke Cherry, Common Sunflower, and Common Yarrow are some examples. Perhaps with a little more care, we can ensure a safer future for these special and essential creatures.