I approach a flock of mountain chickadees feasting on pine nuts. A cacophony of sounds, coming from the many different bird species that rely on the Sierra Nevada’s diverse pine cone crop, fill the crisp mountain air.
The strong “chick-a-dee” call sticks out among the bird vocalizations. The chickadees are communicating to each other about food sources – and my approach.
Mountain chickadees are a member of the family Paridae, which is known for its complex vocal communication systems and cognitive abilities. Along with my advisers, behavioral ecologists Vladimir Pravosudov and Carrie Branch, I’m studying mountain chickadees at our study site in Sagehen Experimental Forest, outside of Truckee, California, for my doctoral research. I am focusing on how these birds convey a variety of information with their calls.
The chilly autumn air on top of the mountain reminds me that it will soon be winter. It is time for the mountain chickadees to leave the socially monogamous partnerships they had while raising their chicks to form larger flocks. Forming social groups is not always simple; young chickadees are joining new flocks, and social dynamics need to be established before the winter storms arrive.
I can hear them working this out vocally. There’s an unusual variety of complex calls, with melodic “gargle calls” at the forefront, coming from individuals announcing their dominance over other flock members.
Examining and decoding bird calls is becoming an increasingly popular field of study, as scientists like me are discovering that many birds – including mountain chickadees – follow systematic rules to share important information, stringing together syllables like words in a sentence.
Sofia Haley describes how she records chickadee vocalizations in the forest.
Songs vs. calls
For social animals, communication is a crucial part of everyday life. Communication can come in the form of visual, chemical, tactile, electrical or vocal signals.
Birds are highly vocal, often relying on vocal communication to effectively interact with their environments and flock members. Temperate songbirds, including cardinals, bluebirds, wrens and blackbirds, have two main categories of vocalizations: songs and calls.
Songs are vocalizations that are used primarily in the spring, during breeding season. Males in temperate regions sing to attract females and defend territories.
Calls are basically any vocalization that is not a song. This category includes a limitless variety of vocalizations that communicate all sorts of essential information.
Most songbird species have complex songs and fairly simple calls. This is why vocalizations sound most melodic during the spring, when birds are attracting mates and breeding.
