For the Birds Radio Program: Ovenbird
One of my great joys of spring is hearing Ovenbirds singing in every woodlot and forest. Well, not quite every woodlot, but up here most wooded areas harbor at least one singing Ovenbird. Their distinctive song, described as “teacher, teacher, teacher,” is loud and ringing, oddly conspicuous to be coming from one of the most difficult birds to actually see. Like most warblers that sing at reasonably low frequencies, Ovenbirds sing from low perches, usually at about eye level. But they can sit stock still for many minutes during a bout of singing, and are colored in soft earth tones, so if you aren’t in the habit of carefully scanning every branch, you’re likely to overlook them.
Robert Frost began his poem, The Ovenbird, with these words: “There is a singer everyone has heard, Loud, a mid-summer and a mid-wood bird, Who makes the solid tree trunks sound again....” I long marveled at not just the loudness, but at that ringing quality that Frost wrote of. But oddly, the loudness and ringing quality aren’t the result of one bird singing—we hear that tonal quality when two birds countersing. According to the Birds of North America Ovenbird entry, “two neighboring males sing their primary song in phase, with the songs of one male following immediately after or overlapping with those of a leading male —a pattern that may continue for 30-40 songs of 3-4 seconds each.” In other words, the song of two male Ovenbirds is, quite literally, resounding. I wonder if Robert Frost knew that, or was just commenting on the loud, ringing quality.
One of the curiosities about Ovenbirds is that they are harmed by an innocuous little invertebrate vegetarian that provides abundant food for robins—the earthworm. Glaciers had destroyed the entire earthworm population of the northern forest, allowing leaf litter to collect for many years at a time, providing the perfect substrate for Ovenbirds, which find much of their food hidden in the cool moist soil protected by deep leaf litter. Where worms proliferate, the leaf litter is broken down much more quickly, and ovenbirds decline. Fishermen can help protect Ovenbirds by not tossing their left-over earthworm bait into the forest. Keeping worms in gardens and lawns helps people, worms, and birds as well.
Ovenbirds make their nest on the ground—it’s a covered little creation that reminded someone long ago of an oven, presumably in the days before fire codes. Ovenbirds also feed on the ground. Sadly, their low-to-the-ground habits make them exceptionally vulnerable to window strikes. And parent ovenbirds raise more than their share of cowbirds. But as long as the northern forests are deep enough and mature enough to support these excellent singers, their song will continue to ring out. But perhaps Robert Frost was right when he wrote of the Ovenbird, “The question that he frames in all but words/ Is what to make of a diminished thing.”