Chickadees Tweet About Themselves
A short tweet from a chickadee can tell other birds their sex, species and geographic location, according to new research.
Chickadees are talkative little birds, with several different calls encoding meanings from indicating the presence of a predator to more complex expressions that express triumph or attraction. Different species of birds may join their flock because chickadees have a distinct call to indicate a source of food.
Their long call is sounded as "chick-a-dee-dee", and has multiple meanings, but the meaning of their shorter sound -- a "tseet" -- was until recently a mystery to the researchers studying the small song birds.
Researchers from the University of Alberta in Edmonton found that the "tseet" call is like a vocal identity badge that uses different tones and decibel levels within the call to identify the sex, species and location of the bird. They studied mountain chickadees, found throughout the Rocky Mountains, and black-capped chickadees, which live primarily in the deciduous northern areas of the northern United States and Canada. The researchers found that each can decode the calls of the other species. However, it may not be easy for them to detect the opposite species’ sex from the call alone.
The research that broke the bird's short tseet down into nine different sound characteristics -- of which only seven were used by the birds to identify themselves -- was reported in the Journal of the Acoustical Society of America.
The researchers' next step is to slightly change the bird's songs, manipulating the individual acoustic features within the tseet call to help determine how the vocal ID badges are constructed.