Editor’s Note: There's a lot to look forward to in spring, including the welcomed hullabaloo of birdsong. The sheer volume of songs and calls can often feel overwhelming for birders, but these sounds offer both an opportunity and a challenge. Follow along with our birding-by-ear series to learn how to better ID birds through their vocalizations. To catch up, be sure to check out part 1, part 2, part 3, part 4, part 5, part 6, and part 8.
In part 7, Marissa Ortega-Welch, steadfast birder and former education manager at Golden Gate Audubon Society, dives into the complexities of bird “accents,” better known as song dialects. Identifying them is a challenge, but if you're up for it, there's a way. This is what you need to know to join the ranks of the linguistic experts.
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When we bird by ear, we like to think of each species having its own constant, recognizable sound. For me, using mnemonics was key to memorizing the songs and calls.
The Brown Creeper sings, trees, trees, beautiful trees.
The Barred Owl hoots, who cooks for you?
The White-crowned Sparrow asks, who me—busy, busy, me?
At least that’s what the White-crowned Sparrow sounded like where I learned to bird, deep in the temperate rainforests of Olympic National Park in Washington state.
But less than 60 miles away as the sparrow flies, on the coast of Washington, the White-crowned has a slightly different song. There it asks, who me—busy, busy, busy . . . trailing off at the end as though it's too tied up to even finish its sentence. It's still recognizable, but it has an obvious local twang.
Now I live in the San Francisco Bay Area, where the White-crowned Sparrows have all kinds of ways to tell you how busy they are. It seems my first birding mnemonic isn’t so relevant elsewhere.
But by noting these local “accents” during my travels and birding experiences, I’ve inadvertently followed in the footsteps of scientists who’ve studied songbird dialects: regional variations in a species’ tune. Both the Bay Area and Puget Sound White-crowned Sparrows are famous for their dialects, and in the 1970s and ‘80s, researchers flocked to these places to analyze them. They detected more than 10 different dialects in the Bay Area alone; a sparrow singing in Golden Gate Park sounded distinct from a male singing just a few miles away near the Golden Gate Bridge.
Donald Kroodsma, an author and ornithologist who specializes in birdsong, tells me that dialects tend to develop in species that are year-round residents. The male birds learn songs from their parents and neighbors. But over time, some individuals might improvise and introduce variations, which are then picked up by the rest of the population, forming a regional dialect. This is very similar to human language, Kroodsma says. "It's culture: learned traditions passed from one generation to the next."
These variations are less common among birds that migrate or travel over short distances because the song-learning pool is not so unique. For instance, when Black-capped Chickadees scope out different areas in search of food, they may swap notes with new acquaintances and mix and merge their songs. This results in a more uniform sound across the major Eastern population. But chickadees that live in isolation west of the Cascade Mountains in Oregon and Washington have developed their own dialects. “They have the most beautiful songs—a cascading series of whistles,” Kroodsma says. “You cross the coastal range 30 miles away, and you’ll never find that song there.” Resident chickadees isolated on Martha’s Vineyard and Nantucket islands off the coast of Massachusetts have also developed their own dialects.
Yet very few songbird species have dialects as strong as the chickadees’ and White-crowned Sparrows’. “In [some], it’s not so obvious,” Kroodsma says. Take the Bewick’s Wren and its extraordinary repertoire. A male Bewick’s can croon 20 different songs. It might learn a dialect for a certain song and a simple variation on another, making it hard for experts to distinguish boundaries. “Most birders who hear a Bewick’s Wren any place on the West Coast will recognize it,” Kroodsma says. “But put that same birder in Arizona or Colorado, the songs are so different.” For birders learning to identify a Bewick’s Wren by ear, a mnemonic won’t be as helpful as paying attention to the overall sound and quality, which are reminiscent to that of a Song Sparrow.
When dialects are identified, they can be revealing in a number of ways. David Luther from George Mason University is examining how White-crowned Sparrows are shifting to a more uniform dialect in the Bay Area, perhaps to sing louder and compete in an increasingly noisy city. Researcher Jay Pitocchelli is studying the songs of four separate Mourning Warbler populations across Canada and the northern United States to track the birds’ migratory paths. He’s collecting data from birders by asking them to record warbler tunes on their smart phones.
Recordings are also one of the best ways for birders to memorize dialects, both in their neighborhoods and in impending vacation spots. The website xeno-canto is a great resource: It’s a crowd-sourced database that allows people to upload sound clips, filter them by location, and listen to them for free. There are currently 359,000 recordings of 9,741 species available on the site.
And if you’re still befuddled by dialects, don’t worry. Birdsong is complex and often subtle in its nuances; even the experts don’t completely understand all its variables. Kroodsma finds the complexity fascinating and doesn’t feel like he needs to impose any order on it. “For humans, who want things in black and white, it doesn’t work that way,” he says.
The same could be said for when I try to impose my mnemonics on birds. They work most of the time, but they aren’t bona fide: They’re human impressions used to fill a natural void in language. Now, I only rely on mnemonics as a tool when IDing a species’ song for the first time. Then, I try to pay attention to tone, quality, and major characteristics. That way when I’m birding in a new place, I can still hear that familiar voice, regardless of the heavy accent.