A Glimpse of an Owl


“There’s something large in the birdbath,” announced my husband as he peered out the dining room window late one recent afternoon. Looking through a kitchen window, I caught a glimpse of what appeared to be a stocky, furry creature with no neck, but could only recognize that it was definitely not a hawk. “It’s an owl!” Rick shouted, already on his way to the basement where we keep the camera. By that time I’d grabbed my binoculars, conveniently hung by the window for these moments, and focused on a bright-eyed Western Screech-Owl (Megascops kennicottii), likely a juvenile (judging by the fluffy/messy feathers the color of tree trunks). We’d heard these owls, on and off, in past years — especially on warm evenings — but had never seen one. And that’s the way they wanted it.

Western Screech-Owls hunt at dusk, night, and dawn, and are much more often heard than seen. Their high pitched hoots — that accelerate with the rhythm of a bouncing ping pong ball — fill the night air like nothing else. (Contrary to their common name, they don’t “screech” but may “bark” when frightened.) Prior to the loss of an enormous American elm tree in front of our house, their voices sometimes drifted through the bedroom window on summer nights. Last night we heard one again, albeit a little more distantly. Perhaps it was this little owl.

Diverse habitats
Found throughout most of western North America from southeastern Alaska and western Canada southward to western Texas, Mexico and part of Central America, their habitat is varied and includes coastal forests, riparian areas, scrublands and deserts. In the Pacific Northwest they can be found in wooded and forested habitat under 6,000 feet — especially with deciduous trees — but may also be found in parks, suburbs, and other residential areas. They weigh 5 to 9 ounces and grow to 7 to 10 inches in length, with a 20 to 22-inch wingspan. Color morphs include the gray Pacific, brown Pacific and Mojave. In general, they are grayish or brownish with heavily streaked feathers. With large yellow eyes, pointy little ear tufts, a yellow bill and a round body and head, they are — in my opinion — adorable.

Food, nests and babies
Their days are spent either in a roosting cavity or perched at its entrance, camouflaged, no doubt planning nighttime hunting adventures which involve locating prey by sight as well as sound. Their generalist diet varies with the habitat; they eat mostly small mammals such as mice, rats, and bats, and large night-flying insects as well as spiders, but may also take some small reptiles, birds, fish, mollusks, and amphibians. I read somewhere that they occasionally take prey bigger than their own bodies!

Like other secondary-cavity nesting birds, Western Screech-Owls roost and nest in natural cavities, such as those excavated by woodpeckers or those formed by branch breakage; in some regions they may nest in cliffs or cactus. They also might use nest boxes if properly placed and dimensions are adequate, but Eastern Screech-Owls are reportedly more likely to use them than Western. During courtship, a pair will often sing duets and the male presents food to the female. Being “socially monogamous,” the pairs raise their young together. Observational studies reveal that pairs show affection, often perching closely and preening one another. The male locates a usable cavity and presents it to the female, sometimes with a tasty morsel in his beak. Throughout the breeding season, the male will roost near the nest cavity; when not roosting, his job is to supply all the food for the female while she incubates the eggs (for around 26 days) and cares for the young. Both the female and the male take turns guarding the entrance of the cavity from predators. After the young have most of their feathers, the female helps with hunting. When the nestlings no longer need her constant attention, she will roost nearby, often touching the male. After the month-old young leave the nest, they continue to be cared for by their parents for another five to six weeks.

Conservation
Although Western Screech-Owl population trends are difficult to study because of their nocturnal habits, populations reportedly have declined slightly between 1966 and 2019, according to the North American Breeding Bird SurveyPartners in Flight estimates the global breeding population at 180,000 and rates them 13 out of 20 on the Continental Concern Score, a relatively low conservation concern. However, the Pacific Northwest population of Western Screech-Owls are highly vulnerable to development (especially in riparian areas), forest clearcutting and other logging, noise pollution while nesting, rodenticides, and vehicular and power line collisionsTheir requirement for snags (standing dead trees) for nest sites have also had a negative impact on their numbers. And according to Audubon, climate vulnerability in the Northwest is fairly high (especially in the Puget Lowlands and Willamette Valley) due to “wildfires that incinerate habitat” and “spring heat waves that endanger young birds in the nest.” The Nature Conservancy of Canada states that Western Screech-Owls “are assessed as threatened by the Committee on the Status of Endangered Wildlife in Canada,” with their small populations threatened by the loss of mature trees that provide cavities for nesting. Although these owls can adapt to degraded habitat and human presence to some extent, maintaining strong populations will require vigorous protection of open forested areas near water in both rural and residential areas.

I wrote about Western Screech-Owls in my book many years ago: “A mated pair of Western screech-owls once graced my neighborhood, but they left forever when a mature tree they used was drastically hacked back during breeding season, a time when birds are intensely sensitive to disruption. I still think of them and how they softly called to each other in the impending dusk, and wonder if they were able to find a more peaceful place to nest. Their eviction symbolizes what can happen when human ignorance and thoughtlessness intervene. Indeed, recognizing that every front, back and side yard—even those within urban areas—is a part of an intricate ecosystem … is the first step toward encouraging rich, natural diversity.” Let’s hope this little owl has a long, rich life.


© 2024 Eileen M. Stark

When Death Supports Life: Trees, Woodpeckers, and Biodiversity


As sad and full of dread as I am about the impending loss of a giant 90-year-old American elm street tree next door, the life that the dying tree supports makes its demise seem much less calamitous. In early March we noticed the familiar tap-tap-tap of a woodpecker on a nearly vertical limb about 40 feet above ground. There, perched on thick, rough bark, was a male downy woodpecker in the process of crafting a perfectly round hole. Since it appeared to be at least two inches deep at that time, I figured that he and his mate had begun excavating the cavity at least a week earlier. The following week the pair ambitiously began work on a second hole, a quarter way around on the same limb, but facing north. Another few weeks passed and we observed them chiseling out yet another hole, this time just below the first one, facing eastward. The branch is angled slightly downward, which keeps out rain and may be less obvious to predators.

What’s with all the holes? Woodpeckers—expert woodworkers of the avian world—including the downy, hairy, pileated, flicker, and many others, hollow out separate chambers for nesting and roosting and, as you’ll read further on, are considered “keystone species” for their crucial role in creating habitat for other woodland species who depend on dead and dying trees in the landscape.

Late in April, it became clear that the third chamber — its depth now at least as long as the birds themselves — would become their little nursery. Excavation of the gourd-shaped cavity continued, but there appeared to be little activity as the month progressed, at least to our eyes and ears, grounded 40 feet below during a very wet, cool spring that kept us indoors more than usual. It wasn’t until the second week of June, when our neighbor told us of baby bird sounds coming from the cavity, that we realized what they’d been up to.

Why snags are essential habitat
With their rotting wood, hollow cavities, broken branches and loose bark, dead and dying trees — known as snags — may actually provide more varied habitat for all sorts of creatures than when they were alive. In addition to providing vital housing for many types of insects (including some pollinators), cavity-nesting birds (around 80 species in North America), amphibians, reptiles, and small mammals (including bats), they provide food and open perches, and double as storage lockers. Woodpeckers also use snags to communicate during breeding season. For species that must roost in cavities during winter, insulated roosting cavities within trees are essential for them to be able to escape frigid temperatures; it can mean the difference between life and death.

But they can’t use just any old tree. A study in Washington’s eastern Cascades found that cavity-excavating birds preferred trees with significantly soft interior wood. “The researchers also found that at-risk species were nesting within burned areas where up to 96 percent of the trees had unsuitably hard wood. This suggests that many trees and snags previously considered suitable for cavity-excavating birds actually may not be.”

The availability of snags falls far short of the need as forests are increasingly decimated and development runs amok; they’re especially rare in urban areas. Removing them steals critical habitat, even if their wood is unsuitably hard. Whenever possible, allow snags to remain in low activity areas that won’t be a problem should they fall apart; when they do they’ll continue to give back in the understory. If safety is a concern but you want to retain a dead tree’s benefits, consult an arborist to shorten the trunk and any branches that might pose a problem (but retain at least 15 feet of height). If you already have a snag, retain or add native shrubs near its base—they will help keep it stable and protected from weather extremes and provide connectivity, leafy cover, and additional food for wildlife.

The Washington Department of Wildlife has more detailed info on these “wildlife trees” and the Cavity Conservation Initiative has an enchanting video that documents, up close, the lives that they support.

Back to the downy nursery story
After we learned of the nestlings, my husband began photographing the adorable babies and their parents, who worked tirelessly to provide them with insects to eat. The nestlings’ voices were loud and strong and photos revealed that they were all male (with little red caps!), and nearly old enough to fledge. Some sources say it may occur at 18-21 days after hatching, although Audubon says 20-25 days; regardless, we knew it would be soon, so we arose very early for several days, in the hopes of witnessing the fledging event. It wasn’t early enough though, because on our third day of morning observation, the loud chirping and queeking heard earlier in the week had dwindled to just one voice: In other words, we missed the main event. Disappointed, we reminded ourselves that the remaining baby’s voice offered hope that we’d at least be able to watch him leave the nest. Why the delay? Many birds, including the downy, begin incubation when the last or second to last egg is laid. Judging by his resistance to leave when the others left, this remaining nestling was likely a day younger, so incubation probably began the day before Mom laid his egg.


We decided that the next day was the day that he’d fledge and since we didn’t want to miss it, we got up at just after five o’clock. For nearly four hours we took turns watching, waiting and photographing while his parents occasionally fed him. They also had their other young to feed, but I imagine he wasn’t much trouble since he stayed put, unlike his brothers who were out in other trees, far enough away that we rarely heard them.

But like the previous day, Junior stayed put. Perhaps he was just too scared to venture out into the world, so we certainly couldn’t blame the little guy. Surely he would leave the next day! We arose early and found he was still at the nest entrance. We checked on him periodically as we fed the cats, made coffee, and had a little breakfast. At 8:05 I checked and he was still at the entrance, so I selfishly went inside for a snack. When I checked ten minutes later I found he had taken to his wings for the first time — and I missed it!! But a little later I heard him in our backyard’s Douglas-fir tree and saw Mom or Dad fly to feed him. In all likelihood, they’re still in the area, staying hidden with their parents busily feeding them, and will remain so for several weeks until they are able to secure food on their own.


Woodpeckers’ crucial connection to others
I gaze up at the holes that lead to the cavities, now silent and empty, and wonder about other species that might benefit from them. Woodpeckers are primary cavity excavators and reportedly do not use nests more than once (although they may nest in a new cavity in the same tree in subsequent years). [UPDATE, June 2023: The sources that state that Downy woodpeckers don’t reuse nest cavities are incorrect, because this year another pair (or perhaps the same parent or parents) are using the exact same cavity!] But their power-drilling labor facilitates unintentional links to other species known as secondary cavity nesters who cannot excavate their own nest sites or roost sites or may have trouble locating other natural cavities (created by broken branches or decayed wood) or artificial nest boxes. Chickadees and nuthatches also may excavate nesting cavities themselves, but they are not considered strong excavators.

Secondary cavity-nesting birds — including bluebirds, tree swallows, kestrels, some wrens, and many owl species — as well as small mammals such as bats and flying squirrels, may utilize abandoned woodpeckers’ cavities. Studies show that areas with a rich diversity of tree-cavity excavators, in conjunction with snags and other forest elements, maintain a high biodiversity of secondary cavity nesters, as well as other forest birds. In a nutshell, woodpeckers play essential keystone roles, are indicators of ecosystem health, and help other species survive.


© 2022 Eileen M. Stark

After a Storm: Dead Wood Gives Life

snaggy-stump

Following a particularly nasty ice and wind storm that damaged or took the life of many mature trees in Northwest Oregon, it’s time to clean up nature’s ragged pruning job and literally pick up the pieces. Or is it?

Clean up sparingly
If there are damaged limbs on a street tree or yard tree close to your house, hire a certified arborist to remove any dangling branches and clean-cut any ragged wounds and stubs left by breakage, particularly if you have a tree that is prone to disease, such elm-damage-ice-stormas an elm. Sharp cuts that don’t leave stubs (partially amputated branches not cut back to the branch collar that look like you could hang a hat on it) will allow for faster healing and may prolong the life of the tree. But if safety is not an issue, consider that natural, important habitat is created when damaged limbs are simply left on the tree. As I wrote in my book, “interactions between wildlife and decaying wood are fundamental to ecosystem functions and processes in forests, aquatic habitats,” and your garden, whether they be wooded or more open.

We’re usually far too eager to remove anything and everything that’s fallen to the ground to keep our yards neat and orderly. Unfortunately, this sort of maintenance can be harmful not only to our backs, but also to dwindling
dead woodwild species that need natural, woody “litter” and some disarray, not homogenous expanses of bare soil, bark mulch, or clipped lawn. In fact, “cleaned up” landscapes are usually outright harmful to wild species, including pollinators and recently fledged birds who need low cover to stay safe. Like fallen leaves, “dead wood” or “downed wood” is so essential that many creatures (and plants) cannot survive without it. So, instead of hauling away branches, logs, bark debris, stumps, twigs and such, be compassionate and leave it (or move it to an appropriate, out-of-the-way part of your yard) so that it can decompose naturally and begin to provide food, shelter, nesting material, or places to raise young. Decomposing dead wood has many other unnoticeable yet complex eco-functions, like supporting fungi that live in symbiotic relationships with plant roots. Eventually, the stuff that may look messy to us turns into fertile soil which supports plants which support insects which support birds, and so on.

Snags are a good thing snag at Smith & Bybee lakes

What about dead or dying trees? Known as snags, with their hollow cavities, broken branches, and loose bark, they actually may provide more varied habitat for all sorts of creatures than living trees do! In addition to providing essential housing for many types of insects (including pollinators), cavity-nesting birds, amphibians, reptiles, and small mammals (including bats), they provide food, open perches and double as storage lockers. Woodpeckers also use them to communicate during breeding season.

Snags are in very short supply as forests are increasingly decimated, and they’re extremely rare in urban areas. Removing them not only steals crucial habitat; it’s expensive. Leave snags in low activity areas that won’t pose a problem if they fall apart; when they do fall they’ll continue to give back in the understory. If safety is a concern but you want to retain a dead tree’s benefits, consult with an arborist to shorten its trunk to snag with female flicker feeding youngroughly 15 feet tall and cut back branches. If that’s not possible and you must cut it down, leave the trunk on the ground where it won’t get in your way and leave the stump. If you already have a snag, retain or add native shrubs near its base. They will help keep it protected from weather extremes and provide connectivity, leafy cover, and additional forage for wildlife.

The Washington Department of Wildlife has more detailed info on these “wildlife trees” and the Cavity Conservation Initiative has an enchanting video that documents, up close, the lives that they support.

 

Designing with dead wood
Although some people view snags and other dead wood as unattractive, more and more of us see them as aesthetically pleasing natural sculptures, issued gratis to the landscape and priceless for wildlife. Keep them, work around them, and incorporatesnag "sculpture" them into your landscape, and the wild ones will thank you.

Consider grouping logs and branches in layered piles, with the largest at the base, in quiet places under trees where they can provide shelter from predators and roosting sites for little ones. Fallen trunks or massive logs can recline individually on the ground, where they might act as lovely focal points that will change over time, displaying dead wood (stump)the quiet beauty that unfolds during all stages of natural decomposition and regeneration. Imagine a “nurse log” in your own yard that will increase biodiversity by providing decades of nutrients and moisture to other plants and soil organisms. While natural, moss-furred nurse logs (fallen forest trunks and limbs) provide complex substrates for regeneration of trees in intact forests, there’s no reason you can’t foster similar function in your yard (but never remove nurse logs from a forest). Surround a fallen giant with native ferns and other shade lovers to blend and complement, and the mystery and magic begins. It rots slowly at first, then begins to crumble away, providing more sustenance for other species. After a few decades, the log will be reduced to nothing but fragments, but the soil—nurtured, enriched, and full of life—will pass on its riches.

A few plant species do best when growing on or next to downed wood. In the Pacific Northwest, Vaccinium parviflorum (red huckleberry), that deliciously berried shrub that hikers know and love, is almost always found growing on a stump, nurse log or other decomposing wood in forests. When I planted red huckleberry shrubs in my yard a few years ago, I buried some rotting wood in the planting hole and added dead branches and conifer cones on top of the soil. So far they seem to like it.

Nest boxes and more trees to the rescue
If you’re like most people and don’t have a snag or a mature tree with decay on your property, consider adding a species-appropriate nest box for cavity nesters like chickadees, chickadee nest boxnuthatches, woodpeckers, swallows, or owls that is sited correctly and is accessible for annual cleaning. Though not as good as natural nest sites due to their inability to insulate as real tree cavities do, boxes are better than nothing.

Lastly, if you’ve lost a tree or have the space for one more, consider planting a regional native replacement (or two or three) that will thrive in the site’s conditions. It’s crucial that we keep planting and protecting, so the cycle can continue.


© 2016 Eileen M. Stark

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