Children may be afraid of the dark – but adults are expected to outgrow such apprehension. After all, we tell ourselves, we basically know what’s going on out there at night, even if we can’t see it.
But the fact is that we are “diurnal” animals – wired, via our circadian rhythms and our visual capabilities, for daytime activity. And our understanding of what transpires among the creatures of the night is limited indeed.
An ongoing study of owls in the Davis Mountains proves it. With the aid of artificial intelligence, scientists are “listening” to the night here. They’re hearing things they didn’t expect.
Dr. Maureen Frank is a scientist at Alpine’s Borderlands Research Institute. Frank and grad student Shelby duPerier are conducting the owl study.
“Flammulated owls do this really soft call,” Frank said. “It's almost like they can throw their voice. You think they're way far away, and then, surprise! They're in the tree right next to you.”
Owl sightings aren’t unusual in West Texas. You might spot a great horned owl in Alpine or Marfa, a barn owl in a farm building in Presidio or a burrowing owl on the Marathon grasslands. And the irresistible elf owl – which, at less than 6 inches long, is the world’s smallest owl – summers in Big Bend.
But other owls have been spotted here only rarely – the flammulated, the northern saw-whet, the endangered Mexican spotted owl. These nocturnal raptors prefer cool forests, where they nest in the cavities of trees. Were the owls seen here just passing through, or could they in fact be living in the Texas mountains?
To find out, the BRI, with support from Trans-Pecos Bird Conservation and Singing Dog Wildlife, deployed some two dozen autonomous recording units, or ARUs, in the Nature Conservancy’s Davis Mountains Preserve and adjacent properties. Placed in rugged canyons, the automated devices have recorded audio for several hours around sunset and sunrise each day for the last two summers.
“Those units will run like that for every single day for months on end,” Frank said. “And that's what's really valuable – is just that volume of data, getting to sample every single night for those species.”
Next, the thousands of hours of audio were run through an AI software called BirdNET – which also drives the popular birding app, Merlin. It’s powerfully effective at identifying bird sounds.
The results were revelatory. Western screech owls were common – that was unsurprising. But there were also elf owls – which were not thought to nest at such high elevations. And there were the mating calls of flammulated and northern saw-whet owls.
These ruddy-feathered owls – only slightly larger than elf owls – hunt insects and small rodents. They weren’t known to nest in the Davis Mountains. And, occasionally, the autonomous recorders also captured calls of the Mexican spotted owl, an endangered species.
Many questions remain. Are flammulated, northern saw-whet and spotted owls year-round residents here, or do they winter elsewhere? These raptors have been spotted occasionally in the Guadalupe Mountain. But do they live in the Chisos? Are owls dispersing and traveling among the Texas “sky islands”?
Yet the study has already changed our understanding of West Texas wildlife.
“There really is a lot to still be discovered in the Trans-Pecos,” Frank said, “because it's so remote. There's a lot of things that we go, ‘The habitat seems right – is it even here?’ A lot of things we still have some pretty basic questions for.”
We don’t need to be afraid of the dark. But we should respect its enduring mysteries.
Owl recordings by Jarrod Swackhamer and Richard E. Webster, courtesy xeno-canto.org.
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