Flying Kittens

“Just hold her like this,” Kurt told me. So I carefully nestled my first two fingers into the soft, warm feathers around the neck of this tiny northern saw-whet owl, cradled her soft, warm torso in the palm of my hand, and secured her brown and white wings with my thumb and other fingers. My heart stopped for a moment, but under those soft, warm feathers I could feel her smaller heart racing.

Kurt opened the sliding door onto the deck of his cabin. I paused to snap a photo of her huge, yellow-ringed eyes staring back at me in the dim light. Then we walked out into the night. As we waited for all our eyes to adjust, I focused on the feel of this incredible being in my hand. So soft, so warm.

Mike Avara, another scientist who is recruiting volunteers for some exciting new owl research in Bayfield County, affectionally described saw-whet owls as flying kittens. Indeed, the feel of her took me back to childhood when my cousin Meggan let me, a member of a family with no pets, hold one of the several very new offspring of her barn cat. Even as a child, the experience provoked an intense sense of responsibility along with the joy of connection to another little life.

Kurt gave the go-ahead, and I opened my hand. There were a few sharp pokes of tiny talons on my palm as she took to the air, and we watched as her fluttering flight became silhouetted against the moonlit sky, then disappeared into the black of the nearby forest.

Regrouping, Kurt and I put on our jackets and headlamps to check the other set of mist nets. About the size of a volleyball net but so delicate as to be almost invisible, mist nets have been used for decades to capture small birds. Each June, our Wisconsin Master Naturalist Volunteer Training Course experiences bird banding in the Moquah Barrens with Master Bander Jim Bryce. In daylight, his nets catch chestnut-sided warblers, brown thrashers, and clay-colored sparrows. Saw-whet owls are the smallest raptor east of the Mississippi—about the size of a robin and weighing just around 90 grams—and so the same nets work for them, too.

For many decades, northern saw-whet owls were caught only incidentally when nets were placed to catch other owls or nocturnal birds, and ornithologists thought that they were rare birds. Then someone decided to play a recording of the male’s song near the nets. Captures skyrocketed! We now know that saw-whets are fairly common across their range, although like most birds they have likely declined due to habitat loss over the past decades.

In the center of his three nets, which he deploys on dry nights from the last week of September through October, Kurt has a speaker set to play the owl’s loud toot-toot-toot call over and over. This sound is easily mistaken for the back-up-beep of heavy equipment, except that the owls are often calling at a time and place where no one would be working. The nets were empty on our second check, but earlier the speaker had blasted right at us as he worked to extract the little owl from the net.

This repeated call is the source of their name, since sharpening each tooth of a saw on a whetstone results in a repetitive sound. The owls make less well-known sounds, too. While exploring a series of recordings, I came across a vocalization nicknamed the “strangled cat whine.” I’ve heard this spooky sound numerous times in dark woods, and never known that it was just a flying kitten.

The owl in the net clacked her tiny beak in dismay at her predicament, but made no other sounds. Kurt is a Master Bander who has been banding birds since 2000, so with his experience it didn’t take long for the owl to be free of the net. Once inside his cabin, Kurt quickly prepared a leg band. Issued by the USGS Bird Banding Lab, the unique number stamped into the aluminum will allow this bird to be identified throughout her life and across the entire continent if she’s ever caught again. Unfortunately, federal funding for the banding lab’s important work is at risk of being cut.

Banding birds like this saw-whet owl has provided scientists with a wealth of information over the decades. Photo by Emily Stone.

Seven to eight percent of the 350 or so saw-whet owls Kurt has handled have already been banded, by him or someone else. These recaptures are an amazing source of information about the movements, ecology, and lifespan of the birds. Even if a bird isn’t recaptured, the measurements Kurt took of the owl’s weight, wing chord length, and age provide valuable data. This owl’s wing chord length of 136 mm, paired with a heavier weight, is what told us she was female. Male raptors tend to be smaller.

We also shone a UV light on the underside of her wing, where fresh feathers glowed hot pink. As feathers age, the UV-reactive pigment degrades, and older feathers look faded. This little owl was hatched just last spring and had only recently molted all her juvenile plumage into adult feathers, so they all glowed brightly.

Band-new feathers on this underside of the wings of this young saw-whet owl reflect lots of ultraviolet light. Photo by Emily Stone.

By this time next year she’ll have some bright and some faded feathers. Maybe Kurt will find her in his nets again. Maybe Mike Avara will discover that she’s raising chicks in one of his nest boxes. No matter what, her few minutes of discomfort at the banding station will help us understand more about her entire adorable species and what we can do to help them navigate a changing world.

Learn more about the volunteer opportunities with Mike and Kurt's saw-whet owl nest box and MOTUS tower research on the Museum's iVolunteer page: https://cablenhm.ivolunteer.com/saw-whet-owl-research

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too. Natural Connections 3 will be published in November 2025!

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our Fall Calendar is open for registration! Visit our new exhibit, “Becoming the Northwoods: Akiing (A Special Place). Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Green Frogs Prepare for Winter

Golden birch leaves glittered across the portage trail as we pulled our canoe up at the landing. My paddling partner and I inhaled deeply of warm afternoon air that was sweetly scented with fall. Hoisting the canoe onto my shoulders, I started off down the trail. It went downhill from there, and not the good kind of downhill.

 

Off the end of a rotten boardwalk we found more mud...

One stretch the portage trail was an old railroad bed and actually quite nice to walk on!

First was the huge patch of sticky mud that sucked at my muck boots and threatened to throw me off balance. A puddle of unknown depth hid slippery rocks beneath the murky water. The next wet patch was spanned by a boardwalk, but the single plank was narrow, slimy, and bounced like a teetertotter where supports had become unstable. Finally, within sight of the next lake, movement near the toe of my boot startled me almost to the point of disaster.

 

Beaver-flooded portage landing.

Big black eyes with golden rims stared up at me from the slope of a rock. Crooked toes gripped the rough surface, and long hind legs braced for a quick escape. The green frog who had jumped out from underneath my boot perched motionless, as if that made them invisible.

 

Looking closer, I was captivated by the coppery shine of their skin, with indistinct dark spots. Despite their name, just a swath around their smile was green, like a smear of Halloween lipstick. Many frogs shift their skin to a darker color on cool days to absorb more warmth from the Sun, which is one reason green frogs (Lithobates clamitans) in the north are often brown.

From their large size, I guessed that this frog was female. Looking back on photos, I could confirm this by the comparing the size of her tympanum—the external ear structure—to the size of her eye. They were roughly equal in diameter. This membrane transmits sound waves to the inner ear. Male green frogs’ tympanums are larger than their eyes, although scientists aren’t sure what benefit that provides.

 

Female green frogs have a circular ear patch called a tympanum that it about the same diameter as their eye. On males, the tympanum is bigger. Photo By Emily Stone.

Throughout the trip—six muddy portages, five lakes, and then back again—we spotted gobs of green frogs at the landings leading into shallow, weedy water, and no frogs at the graveled landings with clear water. Green frogs feed by sitting and waiting for anything large enough to see and small enough swallow. Mud and plants make great habitat for these creepy crawlies, and therefore great habitat for frogs, who also lay their eggs among emergent vegetation.

While we reveled in the pleasantly warm weather, the golden birch leaves on the ground and orange-tinged cedar boughs along the shoreline were a constant reminder that winter is on the way. At home, I’ve been hearing lonely spring peepers call loudly before dawn every morning, from just outside my open windows. Like wood frogs, spring peepers spend the winter just beneath the forest’s leaf litter frozen solid. They are one of the first to wake up and thaw out come spring.

Green frogs can’t tolerate being frozen, and so must find a place to overwinter where they are guaranteed to stay liquid. Often this is simply at the bottom of a wetland or pond. They slow their metabolism and absorb a little oxygen through their skin. Sometimes they take a cue from their cousins and nestle into lake-bottom leaf litter, which gives off a little bit of warmth as it decomposes.

While spring peepers must wake up in a hurry, call like crazy, then rush to lay eggs in woodland pools that eventually dry up, green frogs can take breeding season at a more leisurely pace. Lakes sometimes take a while to thaw. Then the large mass of water takes even longer to warm up. Throughout it all, green frogs don’t have to worry about their eggs or tadpoles drying out before hopping away, even though they don’t start making their banjo-like plunk calls to attract mates until the peepers are almost done.

In fact, green frogs sometimes overwinter as tadpoles, and might not metamorphose until their second summer. By altering the composition of their muscle membranes, the tadpoles maintain their ability to put on a burst of evasive speed even in cold water. This helps them escape predators without wasting energy by moving quickly all the time. Dragonfly nymphs, diving beetle larvae, and water scorpions are all predators who also survive winter under the ice.

My canoe paddle bumped the bottom on one super shallow lake, and I started to worry. What would happen to the frogs and all those beings if this tiny water body froze to the bottom? I later read that green frogs have been observed gathering around springs where groundwater bubbling up will stay at a steady, unfrozen, temperature throughout the winter. They must be good at finding other warm microhabitats, too.

One last green frog watched from a wet rock as we paddled up to the final portage landing. Even more golden birch leaves had fallen overnight, and a lonely migrating loon wailed a farewell from across the water. Each of us was preparing for winter in our own way.

 

Getting out on as many paddling trips as possible before ice up is our way of preparing for winter!

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too. Natural Connections 3 will be published in November 2025!

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our Fall Calendar is open for registration! Visit our new exhibit, “Becoming the Northwoods: Akiing (A Special Place). Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

 

 

 

 

The Mystery of Mast Years

Last week I wrote about acorns clattering across my roof. As it turns out, nuts are raining down on many of your roofs, too! Commiserating over the loud, foot-rolling acorns makes me feel like part of an extended community. Are the oaks part of a similar community? And why are they suddenly attacking us with acorns!

Oaks are mast species, which means that all the trees in an area will produce a bumper crop of acorns at the same time, but only every two to five years. With hundreds of thousands of acorns available, the trees ensure that at least some of them will escape being eaten by chipmunks, squirrels, turkeys, blue jays, deer, and bears and survive until they can sprout and grow. This is known as predator satiation.

Red squirrels are seed predators on acorns.

In non-mast years, the acorn seed predators still survive, but at lower rates. When the oaks do mast, there aren’t enough critters to eat all of the acorns. The seed predators feed greedily and reproduce, but when there are few acorns the following years, their populations drop again. By being unpredictable with their mast years, oaks prevent seed predators from syncing up with the trees.

This same idea applies to parasites. Acorn weevils, knopper gall wasps, and acorn moths lay their eggs in developing acorns so that their larvae have an easy meal. A bacterial pathogen takes advantage of the holes they chew and causes “drippy acorn disease.” The result is the same as a chipmunk eating the seed, but the process takes longer. In addition, the parasites and pathogens are often closely tied to the acorn as a food source, and may not have other options. Chipmunks and other seed predators will eat from an extensive buffet of foods when acorns aren’t available.

While teaming up to satiate seed predators is clearly a good strategy for oaks, scientists are not so clear on how the trees coordinate, sometimes across hundreds of miles. It can’t be totally weather or resource driven, since variations in rainfall and temperature don’t fluctuate as much as the number of acorns produced. Certainly, an oak can’t produce tons of acorns if they are not healthy. But a year with plenty of rain doesn’t automatically result in acorns. During mast years a tree’s growth slows, so sometimes the trees need to put abundant resources toward making wood, not seeds.

One hypothesis about how oaks coordinate their mast years that seems to be gaining support in the scientific community is pollination efficiency. Oaks are wind pollinated. Their male flowers are dangly catkins that release pollen into the wind. The pollen needs to reach the pistils of the much smaller female flowers in order to fertilize the nascent seed. When oaks produce a ton of flowers at the same time and then have warm, dry weather, more female flowers will receive their dose of pollen. If the number of flowers oak trees produce fluctuates from year to year, this could translate into variable seed production, too. According to one study, this is true in “soft” climates, but not the Northwoods.

In harsh climates like ours, oak trees produce about the same number of flowers every spring. Having warm, dry weather that allows flowers to be pollinated AND to develop into acorns is essential, says Dr. Andrew Hacket-Pain who has used data from the Nature’s Calendar Phenology Project to study the correlation. A rainy spring, late freeze, or ice storm can easily ruin everything. Knowing how patchy storms can be in the Northwoods, I’m hesitant to believe that this could coordinate mast years across huge distances.

“In the old time, our elders say, the trees talked to each other,” wrote Robin Wall Kimmerer in her book Braiding Sweetgrass. Do they gossip about the weather like most Northwoods neighbors? Some mycologists theorize that the networks of mycorrhizal fungi who connect a forest by the roots may be the agent of coordination for mast years. “A kind of Robin Hood,” wrote Kimmerer, “they take from the rich and give to the poor, so that all the trees arrive at the same carbon surplus at the same time. Through unity, survival. All flourishing is mutual.”

Mice certainly flourish alongside acorns in mast years. The abundant food source means they have more babies. The same is true for the mice’s predators. Foxes, weasels, ticks, and even saw-whet owls may increase in number when mice are abundant. I’m excited for the potential uptick in owls, because the Museum has just started to recruit volunteers to help with a saw-whet owl study in Bayfield County. Check our calendar of events for details!

From mice to owls to chatting neighbors, oaks, and the mystery of their mast years, are at the center of our Northwoods community.

Author’s Note: Portions of this article are reprinted from 2015 – which was another mast year!

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too. Natural Connections 3 will be published in November 2025!

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our Fall Calendar is open for registration! Visit our new exhibit, “Becoming the Northwoods: Akiing (A Special Place). Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.