natural chicago
Birdsong
and what’s a song is usually determined by context, but sometimes it’s really hard,” Enstrom notes. “It’s definitely not how repetitive or elaborative it is. Calls can be extremely elaborate.” Consider the black-capped chickadee. This puffball-sized bird with black head and throat is named after its call, not its song. When it calls, “Chickadee, dee, dee,” it’s communicating with its brethren, not looking for a mate or chasing off another male from its territory. “A study showed the chickadees increased the number of ‘dee’ syllables based on the level of threat they are sensing,” Beilke says. “If you hear a small flock of chickadees calling, ‘dee, dee, dee, dee, dee,’ a predator is likely nearby.” The chickadee song is a whistling sound in three syllables, with the last two syllables about a minor third lower than the first. “Sometimes you don’t hear the break between the last two notes, and it can sound like two syllables instead of three,” Beilke advises. Chickadees may occasionally sing in winter, but come February, they start in earnest because it’s time to set up nesting territory. Male and female chickadees have the same plumage. The northern cardinal also starts singing in February to claim territory before it begins nesting in early April. With most birds that breed in the Chicago region, only the male sings. But with the cardinal, both males and females sing. “It’s a rarity among temperate zone songbirds,” says Enstrom, who researched cardinal song. “But it’s really
BEGINS IN MID-WINTER by Sheryl DeVore
B
irdsong returns to the region in late January and February, even when it’s cold and snowy and the deciduous trees are leafless. “It’s always exciting to hear birdsong in winter,” says Stephanie Beilke, senior manager of conservation science at Audubon Great Lakes (gl.audubon.org), with headquarters in Chicago. It’s also a good time for beginning bird watchers to start learning songs, because fewer species are singing. The birds that sing in mid-winter live in the Chicago region year-round or are short-distant migrants returning to set up territory. Year-round birds include northern cardinal, black-capped chickadee and mourning dove. Changing hormones and lengthening days inspire them to sing. Birds give both calls and songs. The calls, which can be heard any time of year, are used to keep in contact with one another and alert them about predators. Bird song is used to attract mates or set up nesting territories. “Think of vocalizations done from one spot and out in the open as bird song,” says Dave Enstrom, Ph.D., a retired Illinois Natural History Survey (inhs.illinois.edu) ornithologist. “The line between a call The male northern cardinal sings to attract a mate in late January and February.
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Photo by Don Blecha
Photo by Don Blecha
A black-capped chickadee sings its three-syllable song in winter.
