Avian populations are taking a nosedive. This volunteer is recording the remaining birdsongs.
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LAFAYETTE, Colo. — “Who’s awake? Me too,” says the great-horned owl.
“Yank yank yank!” says the white-breasted nuthatch.
“Pizza, Pizza, Pizza, Pizza!” says the ovenbird.
These are just a few of the many bird song mnemonics a naturalist might employ to identify a bird by ear.
Eric DeFonso, a volunteer naturalist and prolific collector of bird calls, does not have 4,000 mnemonics for the over 4,000 recordings carefully categorized in his computer, nor can he correctly identify each recorded species if quizzed (we know because we tested him).
DeFonso sees his library not only as a personal study tool — though he does occasionally practice his sound ID skills by listening to bird calls in the car — but also as a scientific resource, a database he shares with researchers to further bird sound studies and technologies.
Yet with three decades of birding experience under his wing, experience which spans the mountains of New Zealand to the jungles of Brazil, DeFonso recognizes the threats posed by climate change and habitat loss to bird species worldwide, including in his own backyard.
Video: Chase McCleary and Cormac McCrimmon, Rocky Mountain PBS
Virginia Tech reported last year that North American bird populations have declined by about 2.9 billion birds since 1970, largely due to “agricultural intensification and urbanization… along with climate change.”
Similar trends appear globally. Studies in some of the planet’s most biodiverse locations like Ecuador and Panama show steep population declines for some species, 35 of which dropped by more than 50% from 1977 to 2020.
Negative changes in habitat take many forms, including drying wetlands to felled forests and disturbed grasslands.
“Grasslands have been disappearing for a long time with the advent of agriculture in parts of the Great Plains,” said DeFonso, “and with climate change and changes in rainfall in some areas, tree life grows and actually takes over from grassland.”
Protections for birds have also become a political issue. President Donald Trump weakened the government’s ability to enforce laws that protect most American bird species in the final days of his first term. President Joe Biden reversed the policy when he was in office.
The current Trump administration’s enforcement plans remain to be seen, but the president's Republican allies who authored the conservative blueprint Project 2025 have called for the president to reinstate the limitations on the Migratory Bird Treaty Act.
DeFonso volunteers as a field technician and crew leader with the Bird Conservancy of the Rockies, a Colorado-based nonprofit that conducts survey “bird counts” in areas across the state to track population statistics. He described the work as a sort of “bird census.”
Before working in Colorado, DeFonso traveled and volunteered in Colombia, Ecuador, Peru and Brazil. He guided tours, spoke on the importance of environmental conservation and even appeared on Brazilian national television, where he demonstrated a high-pitched bird call device.
DeFonso’s interest in sound recordings dates back approximately 20 years. He began birdwatching in college and continued after moving to Colorado, where he met a neighbor with a perfectly-tuned ear for bird sound identification.
“I just became so entranced with birdsong,” said DeFonso. “I began collecting bird sounds on CDs, listening to them on my computer, playing them in the car while driving and doing errands.”
He scoured eBay for bird recordings “like looking in a thrift store,” DeFonso said, and began placing international orders for foreign collections like a CD of bird sounds from India.
After years of curating a comprehensive bird call catalog, DeFonso learned about a nature sound recording camp hosted by Cornell Lab’s Macaulay Library, a leader in bird sound research.
“It was like summer camp for birders, and it just got me so enthusiastic about recording,” said DeFonso.
Fifteen years later, DeFonso, equipped with a boom mic or sometimes with just his phone, still travels across the state — and occasionally across the world — to capture bird sounds.
DeFonso now edits his audio with software like Adobe Audition and Wavelab. After removing some of the background noise and isolating each song or call, DeFonso uploads the clip into open-access databases like xeno-canto and the Macaulay Library, the latter in which he has logged 10 videos, 1,863 audio recordings and 5,783 photos.
DeFonso’s contributions connect him to researchers who may be interested in using his recordings for their studies or publications.
“There was a researcher who contacted me some years ago doing a project on LeConte’s thrasher, and he asked if I could give him permission to use my recordings,” said DeFonso.
“I said, ‘Yes, absolutely,’ and later he informed me when his paper went for publication that I was going to be acknowledged for contributing some data.”
DeFonso said he never intended for his thrasher recordings — which he gathered while vacationing in Arizona — to be used for research. Now, having made multiple contributions to other researchers’ projects, DeFonso appreciates the impact his work may have in the future.
“It’s not like I’m contributing the bulk of some data for someone’s study, but I’m playing a part,” said DeFonso. “It's useful, and that’s exciting.”
DeFonso plans on continuing to volunteer in future bird counts, and he still leads tours at events like the annual High Plains Snow Goose Festival in Lamar, which takes place around early February.
His more recent surveys have shown startling numbers in areas once flourishing with avian wildlife.
For DeFonso, more striking than the figures are the sounds — or lack thereof.
“When I got into sound recording, that’s when I discovered how noisy the world is, and I became very aware of the sonic environment in which we live,” said DeFonso.
“I did a survey, this was a year where it had been very dry… and it was quiet,” he said. “When it’s very quiet, you have this feeling of a little overwhelm. It definitely affects me.”
Yet in these “ominous” and unsettling settings, DeFonso finds hope in the resilience of other birds around him.
He often sees birds flying in sub-zero Colorado temperatures and admires their toughness. He thinks about how he might embody some of this fighting spirit himself.
“I’ve had my own doubts about, ‘Why am I here?’, ‘Why am I doing all this stuff,’” DeFonso said, “But the birds inspire me.”
“I learned from them how to be a steadfast person, in a way, and I admire that greatly in them.”
Type of story: News
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources.
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources.
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