BROWN COUNTY, Ind. – Susan Hengeveld gently untangles a tiny saw-whet owl from the net where he’s trapped. It’s like solving a puzzle, figuring out where he’s holding on with his talons, where the netting is threaded under the wings.
This saw-whet clicks its beak at her – quick, outraged pops.
“I know, I know,” she says, and she does. Hengeveld is a saw-whet expert here in the Yellowwood State Forest, a key stopover in the owl’s migratory pattern.
She’s spent years teaching volunteers to place tiny metal bands on Northern Saw-Whet Owls, then watch, listen and log their treks through the forest.
In the grander story of this winged realm, her saw-whet chapter is a hopeful one. Secretive and long misunderstood, this creature is now much better known – thanks in part to her work.
Keeping the dataset going is as important as having started it.
“Long-term datasets are the only way to recognize any trends,” she says. “You can’t just go year to year.” Passing the torch is essential.
The Yellowwood banding station offers something rare to those willing to spend hours in the cold, pitch-dark forest: students and volunteers get to actually hold the owls. Hengeveld believes it sparks a fascination with the work that, soon enough, she’ll hand off to others. Retirement is beckoning.
So she does the delicate, patient work of freeing each little owl, and, once it’s recorded, she always delivers it to a newcomer, someone who has come banding for the first time. She believes there’s something untranslatable about actually holding a bird in your hands.
The owl is small enough to fit in just one hand. There’s a silky warmth to its feathers, an awareness in its piercing yellow eyes. As it pauses to breathe with its holder for a bit, its weight barely registers, but an undeniable familiarity does. Hengeveld says it’s a connection on a biological level.
“It’s so heartfelt,” she says, “I guess in the sense that people feel it — deep down and emotional.”
From birdsong to breakthroughs
Susan Hengeveld started with frogs, many years ago. She wanted to understand how they talked to each other, so she began a PhD studying the neurophysiology of frog-calling patterns.
She found that birdsong, though, was often much more complex and closer to human language. She’d spent childhood summers in wild northern Minnesota watching birds, and she realized she wanted to understand how they learned to sing.
She began a post-doctoral study at Indiana University, focused on how birds learn to physically produce their songs—like how babies learn to walk. She started teaching and didn’t stop for 30 years, from adjunct to tenured to director of Undergraduate Studies for the entire Biology Department.
It was in Indiana where she got to know the saw-whet. The owls are mysterious, keeping silent as they migrate to avoid being picked off by larger birds. Their bark-brown wings fade right into the dark of the forest. They only come out during the long black hours of the fall.
In fact, it was so rare to spot one that scientists used to think saw-whets themselves were very rare. Assuming they stuck to the north, nesting in wintery climates, why were there sightings in Indiana?
Then researchers, Hengeveld included, started keeping track. Catching the owls in invisibly fine nets, ornithologists banded each one with a uniquely numbered aluminum tag, recording the bird’s wingspan, weight and sex.
Hengeveld inherited Yellowwood – Indiana’s first banding station – in 2010. Data from banding stations across the country began adding up, revealing that the owls weren’t staying put.
Each capture or recapture was another blip on a map announcing that, year after year, a silent migration flew further than anyone would have guessed. Not just south, but in every direction, Northern Saw-whets were traveling way farther than researchers had thought.
Now Susan and her husband, Jim Hengeveld, head the banding season in Yellowwood every fall, until the season ends in December. Jim even came out of retirement for a semester to teach Susan’s Biology of Birds class so she could focus on saw-whet research. She has so much to wrap up before she feels she can retire.
Besides the endless paperwork, there’s also work to do in the forest.
Listening, then letting go
In a way, the owl banding season begins in late summer: Hengeveld tells her biology students about what fall has in store. And as winter creeps around the corner, they go into the forest on trips like tonight’s.
When Susan Hengeveld steps into the falling darkness of Yellowwood, she’s listening as best she can.
A bit hawkish herself, her silvery hair is often tucked under a beanie and headlamp, grey eyes always scanning. They don’t fail to notice that a previous crew mixed up the batteries and left them uncharged. Flitting through the plastic bags, she takes inventory with a sigh and an eyebrow cocked at no one in particular.
She needs hearing aids to catch the soft rounded blips of the saw-whet owl’s call, even to hear the throaty sniggering of the barred owl come to eat the smaller birds caught in the nets.
But her hearing aids die. And when they do, she has to rely on the volunteers and their younger ears, or on Jim’s hearing aids, if they have any charge left.
Hours into the night, Jim says he hears a male owl answering the lure, a subtle chirping, brightly reaching out to the imposterous voice.
“You hear what, Jim? No, I don’t hear anything.”
The party holds its breath and listens for the faint call.
“There it is again,” Jim says. “You don’t hear it?”
“Uh-uh.” She shakes her head, barely visible in the dark.
There are a couple of new banders with tonight’s crew. Before the sun set, they unfurled a total of seven nets; an array of three and another of four a short hike away.
Next to each setup they place an audio lure – a small black machine with a speaker emitting the male saw-whet’s cry.
About every 45 minutes, they check the nets, crunching leaves underfoot as they march between them. In the first few rounds, all that shines back at their headlamp beams are spider eyes.
There’s not much wind, and the little there is blows from the South. Hengeveld’s twin sister Karen, who’s come from her Pennsylvania home for her annual photoshoot with the saw-whets, asks in a whisper if that’s a good thing.
“No. I want Northwest winds.” Susan sighs and settles into her camper chair.
Everyone quiets to listen, the crickets and distantly chirping audio lures the only harmonizing instruments as they all wonder if there will be more owls.
By now, it’s far too dark to see your hand in front of your face, let alone the person sitting next to you and, finally, Susan makes the call to close up the nets.
But upon reaching the main, she finds a single owl dangling in the black mesh, unbanded and more than a little annoyed.
Newcomers have the honor of releasing them. Tonight, that is a student named Grace. It’s a personal thing, letting them go.
Grace walks away from the rest of the group. She has to move out of the lights so the bird can reorient itself to the darkness. She sets it on her outstretched arm; this is the tricky part. Will the little creature topple over if she lets go? Sometimes an owl will take off immediately, but this one seems content to rest there, just for a minute.
Then suddenly it leaps into the blackness, moving on with the barely audible rush of its tiny wings. The saw-whet continues its migration, and Hengeveld looks forward to her own—with thousands more birds to see and no time at all to waste.