There are a lot of unusual sounds out there in the natural world. Here’s one from the nighttime forest, often heard this time of year.
No, it’s not a school bus backing up.
It’s a tiny owl, the northern saw-whet, and it’s a lot more common than bird surveys suggest. As you might imagine, small birds active only at night are not easy to survey. Also important to note is that because they're the favorite meal of the much larger barred owl, their survival depends on keeping a low profile—usually under cover of dense conifers.
As for the name, “saw-whet,” their repeated toots reminded an earlier generation of the sounds of saw teeth being sharpened on a whetstone or grinding wheel.
Weighing in at about three ounces, these small owls with big eyes, and seemingly tame demeanor, have captivated people lucky enough to experience a saw-whet encounter. However, despite over 100 banding stations set up nationwide to track their movements, not a lot is known about this most charismatic and mysterious owl.
Biologists broadcast a male’s toots to lure migrating birds in to delicate netting. The owls are extracted with care, their age and sex determined, and feather-light bands placed on their legs.
Results confirm that—unlike most owl species—the northern saw-whet is highly migratory. Most head south through New Hampshire in October, towards winter residencies as far south as Virginia and perhaps beyond. As for New Hampshire’s winter saw-whet population, we don’t know how many are Canadian natives that pushed south for the winter, or New Hampshire natives, that stay put year-round.
Persistent snow cover makes catching mice—their preferred prey—a real challenge. But when they succeed, one mouse provides more than one meal for these captivating sprites of the forest.