Brooklyn Bird Watch: December 14
Carolina Wren. Scientific Name: Thryothorus ludovicianus.
Today, Brooklyn Bird Watch features a Heather Wolf photo of a Carolina Wren. The Carolina Wren is an interesting bird and is third on the list of the five most common Wren species in New York State. The Carolina Wren is a shy bird that is definitely heard more than it is seen. Their range map covers basically the Eastern third of U.S. all the way up the coast from Florida to New York State. The Cornell Lab points out that the CW continues to expand its wintering habitats further and further north in recent decades, and in the Summer “it can seem that every patch of woods in the eastern United States rings with the rolling song of the Carolina Wren.” It is also noted that this bird can sing extremely loud for its relatively small size.
Heather Wolf’s photo perfectly matches the Cornell Lab description of this bird, that is, the “rich cinnamon plumage, white eyebrow stripe, curved beak and long, upward-cocked tail.”
The CW usually mates for life, which would classify it, of course, as a monogamous bird. A pair will stay together on their territory all year, and forage and move around the territory together. They eat mostly insects, especially caterpillars, beetles, true bugs, grasshoppers, crickets, and others. They will also feeds on spiders and snails. Sometimes they will catch and eat small lizards or tree frogs. They like to visit bird feeders, especially if there is suet.
Only the males actually “sing”, and have a rather extensive repertoire of at least twenty different phrase patterns while the female CW generally has a more clipped chirping sound. Even though the male is the primary singer of the species, pairs have been known to sing together, for example, “interweaving their songs such that they sound like a single bird singing”. Sometimes a pair will defend territory by singing together. Nevertheless, female Carolina wrens do possess song control regions that would appear to make them capable of singing with repertoires like the male. Due to vocalizations that they occasionally make with the male, it has been suggested that song perception plays a role and is of behavioral relevance. And the male CW apparently like to just sing, and then sing some more. It has been reported that one captive male Carolina Wren sang nearly 3,000 times in a single day.
As far as courting goes, Audubon points out: “A 2006 study suggested that the correlation of tail length and body size in males, wing length in females, and lifespan for both sexes were signs of individual quality, and the wrens of high quality tend to mate with like individuals. The courting, as well as antagonistic encounters, that involve the tail fanning and wing drooping, were suggested to be possible signaling tactics. Age and life experience are not thought of as significant for potential mates due to their relatively short lifespan and sedentary lifestyle.
The Carolina Wren probably daydreams about global warming theories. They are known for their sensitivity to cold weather, with the northern populations decreasing markedly after severe winters. The gradually increasing winter temperatures over the last century may have been responsible for the northward range expansion seen in the mid-1900s.
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