Birds the world over greet the morning with their songs. Some are hauntingly melodic, like that of the hermit thrush. Others sound liquid and alien, like brown headed cow-birds, who as brood parasites are raised in the nests of other birds. Whether bird songs lighten your spirits or simply wake you from peaceful slumber (blue jays anyone?), they are a ubiquitous part of life on the blue planet. But what exactly are they saying?
Scholars have debated for centuries about animal languages. Do animals use syntax, or is all that noise just alarm calls and mating grunts? In recent studies, Constantine Slobodchikoff and collaborators famously pieced together prairie dog syntax. It turns out that prairie dogs are very adept at describing their worlds. If you are wearing a yellow shirt with a black hat or green swim trunks with a helmet when you walk through Gunnison's prairie dog territory, it matters to them. They will describe your height, weight, and attire in detail to their colony mates.
Elephants communicate with one another, at times grumbling at frequencies lower than humans can hear, with voices and postures that scientists have used to predict behavior. And it turns out that dogs understand human intonation and speech.
But what about birds? What does their communication consist of? In a 2016 edition of Science, Mylene M. Mariette and Katherine L. Buchanan showed that bird songs can carry messages for their embryonic offspring. About five days before their eggs hatch, zebra finches exposed to temperatures above 78.8℉ sing a special climate song to alert their offspring. In controlled experiments, the authors found that particular songs, in conjunction with higher nest temperatures, corresponded to decreased nestling mass and altered begging patterns. Since smaller size can help animals thermoregulate in hotter climates, scientists think that the subtle songs help baby birds acclimate. This may be advantageous in the midst of climate change.
But those songs don't just affect the mass of the birds. Zebra finches who hear calls when still in their shells, also tend to select nesting sites that are hotter on average. A short melody heard in the egg likely affects a host of decisions the finches will make throughout their lifetimes. Even if finch language doesn't consist of complex syntax like human speech, parents are still able to help their children understand the world around them through their vocalizations. Katherine Buchanan calls this emerging avenue of study “paradigm changing.â€
During experiments like these, bird vocalizations are important to just two groups: the birds and the researchers studying them. Although some scholars believe animal's voices are only important to members of the same species, naturalists and educators Jon Young and Dan Gardoqui are trying to shift that perception with something they call the art of bird language.
To these authors of What the Robin Knows, bird language reveals the complex, and sometimes fraught relationships of forest denizens. According to Jon Young's decades of observations, and his studies in the Kalahari Desert, bird calls and movements are a lot more than just noise. They can signal the types of predators nearby or be used to communicate with mates. During my own bird language journey, I've heard the companion calls of cardinals as they “chip†back and forth, a signal Young translates as, “Are you there?†“Yes, I'm over here!â€
Calls of alarm–the high-pitched “seeeee!†of a robin or an angry crow's caw–are some of the more obvious signs of danger that a bird vocalizes. A cluster of cackling grackles and robins by a river's edge once alerted me to the presence of a swimming mink. And I've used the mobbing behavior of crows more than once to witness owls trying to get a good morning's sleep before dusk.
Alarm calls are used for more than just the species who made it—squirrels, chipmunks, and other songbirds are known to respond to warnings to duck for cover from a common predator. Once I encountered a cacophony of sound consisting of five species of birds and one angry squirrel clustered in a tree. Who was at the tree's crown? A sharp-shinned hawk munching on a cardinal.
Humans are also known to use bird language for survival. For an urban dweller it might be hard to imagine needing a bird to tell you about predators. But what if you were a Kalahari bushman in the land of lions and leopards? Young credits the Bushmen's keen knowledge of bird language for helping them survive among fierce predators. During a lecture, he recounted asking a San man, “Why are you so good at knowing what the birds are saying?†The answer: “A long time ago, lions ate a lot of us.â€
Animal vocalizations can mean a lot of things. To some, they indicate the ability to adapt to climate change and hope for the future of species. For others, they reveal the inner workings of a multi-species landscape. The next time you hear the screech of a red-tailed hawk hunting with her mate, or see a handful of chirping robins popcorn up from the ground, take notice. The birds are saying more than some people have ever imagined.
 Jennifer DeMoss is a doctoral candidate from the University of Georgia's Anthropology and Integrative Conservation programs. She is currently in the field researching social relationships between people and landscapes within educational programs in the Nature Connection Movement. She uses tools such as GoPro cameras strapped onto her head to video social interactions as part of her research. When she's not interviewing people, she loves to camp, practice primitive skills, carve spoons, and swim in spectacular northern lakes. You can contact Jen at jdemoss@uga.edu. More from Jennifer DeMoss. |
