Carolina wren photo by Jim Phillips
On my New Years Day walk in flood plain woods along the Des Plaines River I heard a bright chattering wren call from a patch of weeds. A busy mixed flock of juncos, tree sparrows and goldfinches had brought a pause in my walk; I wasn't expecting a Carolina wren. One I saw here in Miller Meadow in early fall was the first since 2013.
I saw and heard a Carolina wren in the same area twice more in January, and just maybe two on one visit. Then February – deep snow and quite cold. Would these denizens of warmer climate survive the winter onslaught?
Northern Illinois is on the fringe of Carolina wren range, and they are famously sensitive to severe winters. Cornell's All About Birds says, “The gradually increasing winter temperatures over the last century may have been responsible for the northward range expansion seen in the mid-1900s.”
When I moved to this area from the west in the mid-70s, my first season at south suburban Sand Ridge Nature Center was my introduction to these entertaining and vocal birds. One even nested around the garbage cans next to the center's garage. After the severe winters of the late 70s they disappeared. After 1976 my next record at the nature center was not until 1985, and then they were again regulars. State wide, Illinois Christmas counts found 800 individuals in 1976, but only 33 in 1977.
Largest of the eastern wrens, rich brown with a white stripe over the eye and distinctly curved bill, Carolina's are also easy to tell from our other wrens by their musical songs. One version may sound a lot like a titmouse's “peter peter,” but more often the song is three parted, written as “tea-kettle tea-kettle.” A male – unlike most wrens only males sing – might repeat the same pattern over and over, or mix in variations. All About Birds reports that a captive male sang nearly 3,000 times in one day. Both sexes use a variety of calls and chatters. A pair may sometimes chatter in duet, or you might hear neighboring males answering songs.
Despite setbacks during severe winters the range of Carolina wrens expanded north through the 20th century, through the northeastern U.S., well into Ontario, and as far as Minneapolis and Montreal. Less frequent severe winters and reforestation probably enable range expansion, and there is evidence that proliferation of feeding stations has contributed. Insects and spiders make up the bulk of the diet of Carolina wrens. Suet and peanuts are favored foods at feeders, with reports of mealworms being attractive.
Carolina wrens were no strangers to area Christmas counts this past winter. We tallied a record high of 12 on the Calumet City/Sand Ridge count. Farther north, four were found on the Chicago Urban count and Barrington reported three,.
I'm surely not the only one curious about the effect of our February weather on local Carolina wrens. A post on Illinois Birding Network from “southernmost IL” reported that 8 birds that were being seen had all disappeared after the February cold spell. Others from DuPage, Kane and other parts of Illinois have been seen in February. A response noted that one of a pair sighted last year in LaBagh Woods was singing after the cold. I haven't found the Miller Meadow wren since January, but I'll keep looking, and will be interested to see how many of these charming birds show up for the spring count in May, and the next Christmas counts.
John Elliot
John is a CAS Board member and long-time birder. He leads bird walks, and is a font of local conservation knowledge as a former naturalist and education manager for the Forest Preserves of Cook County.