Research News: Chickadees have a lot to say
A hawk stealthily approaches your yard, seeking to make a meal of a songbird at the feeders. In a flash the predator swoops through the yard and the songbirds scatter. The chickadees issue high-pitched “chick-a-dee” calls, rush to find cover, and continue to scold the predator. To our ears these high-pitched calls signal alarm, and that information is not lost on the songbird community.
Recent research on Carolina Chickadee vocalizations confirms that the various chick-a-dee vocalizations are part of a structurally complex vocal system that is used to convey a large amount of information. Recording calls of free-living chickadees in winter, Todd Freeberg of the University of Tennessee associated different call types with various behaviors and contexts. Call structure changed depending upon the signaler’s proximity to the ground, flight behavior, and the presence of an avian predator. For instance, the chickadees produced more of a specific note and call type when an avian predator flew by. The high-frequency sounds are easy for other birds to hear, but are difficult to locate in space. In effect, chickadees can warn their flock mates about the danger without announcing their own position to the predator. According to Freeberg, a large number of messages can be encoded in the note composition of the chick-a-dee calls. This begs the question: What are the birds saying about us?
Source: Freeberg, T.M. 2008. Complexity in the chick-a-dee call of Carolina Chickadees (Poecile carolinensis): Associations of context and signaler behavior to call structure. Auk 125:896-907.