HOW A WARMING CLIMATE IS AFFECTING BIRDS IN NEW MEXICO

I had the opportunity to speak with University of New Mexico ornithologist Ethan Linck and his colleague Ryan Terrill last month about how our changing climate is affecting migratory and local bird populations and what effects we may see in the future.


Global bird populations have dwindled as insect populations decrease. New Mexico saw this firsthand last year when a combination of extremely cold weather and scarce food led to a mass bird die-off. This year, our state is faced with a drought that has killed piñon and juniper trees—according to the U.S. Forest Service, between 2014 and 2015, that number is approximately 350 million piñon and juniper trees across almost 3 million acres in the southwest. These trees provide shelter for several ground-dwelling animals, as well as many species of birds. These trees also house insects that now no longer have a habitat, meaning less food for birds. Without this shelter, migratory birds must shift their routes, moving to higher elevations to escape the heat and find shade. Dr. Linck uses the term “escalator extinction” to de- scribe this process of constantly moving to higher elevations, commenting, “… eventually, they run out of mountain.” In- creasing agrarian land and development in low elevations is also contributing to this vertical mobility, as birds have fewer and fewer undeveloped areas to nest in.

As our monsoon season continues to arrive later and later in the summer, we may see fewer migratory birds that had previously stopped in New Mexico to molt their feathers, explains Terrill, who has been studying the effects of erratic monsoon seasons on these populations. Terrill points out that “birds have to molt,” citing a study conducted in the 1970s where birds were kept in captivity and deliberately underfed in order to prevent them from molting. Upshot: birds molt anyway, albeit very under-feathered. The monsoons provide greenery and vegetation, which in turn provides food in the form of insects and shade from the heat. Without stable annual monsoons, their breeding season will also be affected, because after molting these birds head further north to breed during the late summer and early fall. With late monsoons, native birds will have later breeding seasons and a double breeding season, termed “second spring,” during the fall in places like southern Arizona, due to plentiful plant and insect life.

Terrill gave the example of the Painted Bunting to illustrate how birds are already being affected. The Painted Bunting travels from Texas to Florida along its migratory path and in previous years would have a wet monsoon area to look forward to, but lately due to later monsoons, they’ve instead been landing in alfalfa fields. Traditionally they would use a tropical dry forest, but without monsoons they’re instead becoming dependent on human water sources used for agriculture. Just two years ago, Mesa Chivato in Thoreau, N.M. experienced hundreds of molting migratory birds, but now they’re nearly nonexistent there.

I asked both scientists what they think the public can do to help, and what sort of policy they’d like to see from our political leaders. Linck said we need to “decarbonize yesterday” and points out we haven’t fared well by hitching our economy to industries like oil and gas.

He pointed out that climate solutions “are not rocket science” and that it comes down to ensuring healthy, connected habitats. Terrill stated we need to em- brace “full annual cycle conservation,” noting that birds pass through multiple states on their migration that can each have radically different climate and conservation policies, showing the need for nationwide protections.

I ran a few policy ideas by Linck and he agreed they were great places for the
local government to start. One idea is the requirement of anti-collision designs for windows, a second is controlling the stray cat population and increasing aware- ness of the disproportionate bird deaths caused by domestic cats, and finally, ban- ning pesticides. What ordinary civilians can do is plant native plants and trees, especially fruit-bearing trees and shrubs, and participate in helping scientists track bird populations by logging sightings onto the eBird app or website.