Thurston's Birds

Bird communication, update on new research

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Most of us are familiar with at least some of our local bird songs, chatter and chirps. (Serious birders call all of those vocalizations.) Birds communicate their location to others in their flock (for example, the constant “chic-a-dee-dees” exchanged by the chickadees visiting your winter bird feeder). And in the spring, many of them will sing elaborately to establish and defend breeding territories and to attract mates.

And, of course, some birds are marvelous mimics – YouTube is filled with parrots speaking all kinds of remarkable words and phrases. Some of our local wild birds are good mimics – I have heard numerous Stellar’s Jays imitate the call of the Red-tailed Hawk in order to – well, I’m not certain what that Jay really has in mind; maybe it’s to scare me away from approaching closer, or maybe to just have some fun.

Steller's Jay - Regularly heard calling from nearby trees
Steller's Jay - Regularly heard calling from nearby trees
PHOTO BY LIAM HUTCHESON

And that last “maybe” illustrates a challenging problem for ornithologists interested in better understanding bird communication. Both the brains and the vocal biology of birds are very different from that of mammals, including us. It’s a challenge for researchers to get beyond our mammalian prejudices and our biological limitations.

One human limitation is that we cannot hear the full range of bird vocalizations, with some being a pitch above or below our hearing abilities. Also, some bird “talk” is so quiet or full of subtle differences that they cannot be easily detected. And, given our prejudices (and researchers have them, too), we humans have assumed if we cannot detect them, then they are not there.

There’s a bird species in Europe, the Greylag Goose, that has been intensely studied since the 1930s. Thanks to these ongoing studies, we know quite a lot about this bird’s migration and breeding habits. These birds vocalize with a rather boring “honk,” not all that different from our familiar Canada Goose.

Very recently the researchers decided to investigate Greylag Goose vocalizations in detail using recording and sonagraphs (a sonagraph is a visual depiction of a vocalization and helps humans get beyond our auditory limitations).  It turns out that these geese have at least ten different “honks,” including special honks that mated pairs use to “talk” with their mates (and which neighboring geese ignore).

This is a male Superb Fairywren
This is a male Superb Fairywren
Photo by Liam Hutcheson

Another interesting insight into bird vocalizations was found almost by accident. There are common small birds in Australia called Fairywrens. A researcher was interested in these birds’ nesting behavior (for example, whether they help raise each other’s young) and placed small cameras in numerous nests and, almost as an afterthought, added microphones. What was discovered was amazing. Each female, when returning to the nest to incubate her eggs, uttered a soft vocalization (what the researcher calls an incubation call). And each female’s incubation call was subtly different from the others.

And, also remarkable, after hatching, the young in each nest had their own unique begging call. And it was not genetic – eggs were shifted from nest to nest and the hatched young had learned their begging call variation from their foster mothers. Apparently, even in the egg, these birds were learning a unique vocabulary from their incubating females, related or not.

These and many other studies of avian vocal communication pose challenging questions about the nature of language. Generally, we regard language as one of the unique defining human characteristics. It is the means by which knowledge is passed between people and thus can accumulate over generations.

We know (or think we know) that young avian songbirds learn their species’ song by imitating the song of older males. But those fairywren studies, and others modeled on them, demonstrate that birds have other means to pass unique vocal features (dialects, if you will) from generation to generation, and that these dialect differences are learned. 

Another research study demonstrates the practical value of subtle vocal differences. The Siberian Jay, a species similar to our local Jays, exhibit aloud alarm calls to warn others of danger. To our ears, these calls all sound identical. However, detailed study of Jays’ warning calls detected subtle differences. Even young chicks could hear these differences and reacted differently and appropriately, ducking when hearing a warning call about an avian predator and avoidance jumping when hearing an apparently different call that a nearby snake provokes.

Every time I read about new avian research, I’m struck by the fact that birds have intellectual abilities far greater than we casual bird watcher’s give them credit for. And I think about how much more there is to recognize in life around us and how difficult it is to overcome our own human limitations and prejudices.  

What a notion: to imagine that those chickadees or juncos (or starlings, for that matter) are possibly talking with each other as individuals and that different flocks of the same species might have their own vocal dialect. Learning even a bit about these little-known bird linguistic abilities provides a radically different perspective about what might be really going on with our avian neighbors.

George Walter is environmental program manager at the Nisqually Indian Tribe’s natural resources department; he also has a 45+ year interest in bird watching. He may be reached at george@theJOLTnews.com

Photos for this column are provided by Liam Hutcheson, a 17-year-old Olympia area birder and avid photographer.

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  • MamaBear

    I loved this piece! Thank you, George. I also love Liam's photographs. They make so clear the markings of various species.

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