It’s a call so distinctive that it’s the source of the bird’s name, not only in English, but also in Native American languages. Chickadees are found across North America. Their “chickadee-dee-dee” call is an alarm – the more “dee-dee-dees,” the more serious the threat – and it’s only one element in their vocal repertoire. Scientists have been listening closely to these songbirds in our region. What they’ve heard reveals the surprising cultural variety of the creature world.
Dr. Ben Skipper is a professor at Angelo State University.
“With the chickadees, it became more about the song and the interest in – if I can be open with you – doing some research in some very exciting and beautiful places,” Skipper said. “These would be the sky island mountains of southeastern New Mexico and Texas.”
In recent summers, Skipper has fled the sultry Texas plains for the Davis and Guadalupe mountains, as well as the Sacramento, Gallinas and Manzano ranges in New Mexico. These isolated heights are the most southerly abodes of the mountain chickadee.
Four to 5 inches long, with gray flanks, black-capped heads and black stripes above their eyes, mountain chickadees are year-round high-country residents. In summer, they cache seeds by the thousands, in countless nooks. In an impressive show of memory, they later recover those stores. The males sing a simple song – a series of high, monotonic notes. That makes them ideal for studying the phenomenon of birdsong “dialect.”
There’s an enduring assumption that nonhuman creatures are “hard-wired” in their behavior, and that only our species is capable of teaching and learning, of transmitting information apart from instinct. But birdsong belies that assumption. Like a baby babbling, a newborn songbird experiments with a host of noises. But males also listen to and learn the songs of their species.
“It's analogous to human speech,” Skipper said. “We learn what we hear. A chickadee may not learn his father's song. He may learn his neighbor's song, in the same way that you and I may form affiliations that are different from our parents or guardians or whoever they may be. So it is a cultural evolution that's occurring, and it's fast. It's fast.”
Dialect is a familiar aspect of human language. Often, the more self-contained the community, the more distinctive the dialect – think Appalachia, or Boston. The sky islands are similarly self-contained. Mountain chickadees need woodlands, and, from generation to generation, most live out their lives in a single high-country forest. Does each range have a distinctive chickadee dialect?
To answer that question, Skipper and his students hike the ranges, with recording gear in hand. In the Davis and Guadalupes, there was disappointment – the chickadees were there, but they weren’t singing.
“They're dry forests to begin with,” Skipper said of the Texas mountains, “but they have been drier in years, and I suspect there's some interplay between the drought conditions those high forested areas are experiencing and the lack of singing activity that we observed there.”
In New Mexico they had better luck. They made recordings of chickadees in the Sacramento Mountains. They were markedly different from those in the Gallinas, which in turn were distinct from the Manzanos chickadees’.
“So within the patch, which is quite large, they all sounded the same,” Skipper said. “But as soon as you jumped over to the next mountain range, it was a different song. Now the question we have is, do they still recognize each other?”
Skipper noted that as a Southerner, he can mostly comprehend a New Yorker’s dialect. Can a chickadee from the Manzanos “understand” one from the Guadalupes? Do they recognize one another as the same species? Skipper hopes to test that next.
But his research has already revealed the complexity of creaturely communication.
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