Now's the perfect time to check for cavities

Now's the perfect time to check for cavities
John C. Lorson

Take time to spot cavities in trees, rock outcrops and even on buildings at this time of year, as birds and other creatures will be in hot competition for nesting sites in the next several weeks. You might be surprised at what you’ll find if you look closely. Beginning on the left and moving clockwise, you’ll see the cavity-riddled snag; next, from a hole in the top-right portion of the tree, an eastern screech owl dares a quick glance; and finally, the bird reveals itself entirely to bask in the sun.


Something tells me this week’s headline will instantly put a smile on the face of my dentist. He’ll nod his head and agree. "Yes, now is the perfect time to check for cavities."

Then he’ll read a bit further and learn I’m talking about an entirely different type of cavity — one that most absolutely should not be found inside your mouth — unless, of course, you’d be willing to open up wide to host a family of wood ducks, squirrels, woodpeckers or owls for a season.

The cavities I’m interested in are those that offer a near perfect opportunity to view wildlife in its most reliably present state. I’m talking about the voids, holes and hollow spaces found in trees, snags, rock faces and even the walls of buildings. These spaces offer move-in-ready, often ideal nesting habitat for all manner of small creatures.

And while my friends in dental practice would undoubtedly say any time is a perfect time to check for their brand of cavities, when it comes to the ones I’m looking for, the last few weeks of winter offer ideal conditions for spotting nesting holes.

One of the more beautiful aspects of the season is the sheer austerity of the landscape. Simple, bare and shorn of leaf and color, the monotone world reveals its imperfect truths. The stand of hardwoods that seemed so lush and flawless mid-summer has thinned to uncover the storm-scarred beech, a thick limb sacrificed to the wind or the lifeless, hollowed remains of a mighty ash, slain by a voracious beetle that has stolen even its name (the emerald ash borer). But often what charts as a loss for an individual tree scores a win for wildlife. Injury brings opportunity for creatures who depend on such high and safe havens as an out-of-sight place to rear their young.

While the trees are still bare, walk a chosen stretch of trail or stalk your favorite parkland or woodlot with the specific notion of locating as many cavities as you can. Go in the late afternoon or early morning when the sunlight hits the trees in a manner that casts crisp shadows and blazes light into the inner sanctum of such hideouts. I’ll bet you’ll be amazed at just how many cavities and nesting sites you’ll find.

Incidental to these finds, you’re sure to spot a good share of last year’s “woven” nests as well. Many of those will be repurposed into this year’s homes — sometimes for the same birds and sometimes for other individuals or species altogether. Timing has a lot to do with “who gets what” as the migration ramps up and travelers begin to arrive back at the nesting grounds.

While on the subject of timing, an added benefit of searching for cavities right now, even though the woods have been leafless and available for months, is you may just catch a nester in the act. In the past week I’ve begun to see and hear male red-winged blackbirds staking claims and defending territory. And while the red-winged blackbird is not a cavity nester, they are a reliable harbinger of spring. It’s clear they’re here to stay. Other species will follow apace.

Even if you find cavities that seem ideal for nesting yet nothing of the sort is happening just yet, make a mental note of the location, sketch a simple map or drop a pin on your GPS unit if you’re one to carry such technology afield. Once vegetation begins to leaf out, the easy-to-see world of winter becomes a disorienting tangle of green, and you might well need all the help you can get to find your way back to watch a young family fledge.

I should mention once you’ve located an active nesting cavity, be sure to mind your manners. While finding an animal’s home can offer unbeatable opportunities for observation, if a critter feels its stealth — and consequently its safety — has been compromised, it may abandon a site. Keep your distance, keep things quiet and visit only occasionally.

Good luck in your search, and here’s hoping you’ll find dozens more cavities than your dentist.

Remember, if you have comments on this column or questions about the natural world, write The Rail Trail Naturalist, P.O. Box 170, Fredericksburg, OH 44627, or email Follow along on Instagram @railtrailnaturalist.

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