Wilderness Underfoot: One bird’s song of survival

StoryImage( ‘/Images/Story//Auto-img-113702397017472.jpg’, ”, ‘The black-capped chickadee – Poecile atricapilla. Despite its variety of warning calls, this bird is no coward. The chickadee is legendary for its tenacity around humans; it will sometimes take birdseed and other treats right out of your hand! Unfortunately, these bright and valiant little birds have seen their numbers reduced by a threat for which they have no call: West Nile virus. ‘);
StoryImage( ‘/Images/Story//Auto-img-113702398117472.jpg’, ”, ”);

The black-capped chickadee is a chatty little bird with lots of angst. It is one of our most abundant cold weather birds, and a frequent visitor to the winter feeder.

The chickadee’s call is described as “chickadee-dee-dee-dee,” but a study completed last year shows its song is far more complex than ornithologists ever imagined. The study, conducted by Chris Templeton at the University of Washington, found that chickadees have a sophisticated system of calls for alerting their flocks to potential threats.

Templeton took 5,000 recordings of chickadees making alarm or “mobbing” calls. Most of the variations in calls couldn’t be detected by the human ear, while others were easily heard. For accuracy, the recordings were put through spectrographic analysis, in which sound waves are graphed and compared. The results amazed the researchers.

Thirteen different predators had set off various alarm calls in chickadees. These calls were specialized, depending on whether the threat came from a terrestrial predator, or one that was perched or flying overhead—and whether it was smaller and more agile, or larger and less agile. Typically, the chickadees added more dees to the dee-dee-dee notes at the end of the call, saving their loudest and lengthiest outcries for the most dangerous threats.

When confronted by the presence of a great horned owl, for example, the chickadees were less vociferous than they were with swifter, more adept raptors such as the pygmy owl or the kestrel. Rather than fleeing, however, the calls incited the chickadee flock to mob and harass their predators to drive them away.

In our region, hawks and domestic cats pose the greatest predatory threat to chickadees and other songbirds. It is not uncommon to see chickadees mobbing

these predators.

From the Jan. 11-17, 2006, issue

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