By KEVIN NEVERS
Think of it as a ghost, passing silently through Duneland’s forest
fastnesses and deeps on cold clear nights in October and November on its way
south to a winter roost.
It may as well be invisible, for it’s rarely seen. If it tarries here, as it
sometimes does, it goes to ground in secret stands of evergreen, and if
you’re optimistic enough to search for it—look for its whitewash on
trees—take a compass and be prepared to get lost.
It’s the Northern Saw-whet Owl. For ornithologists it’s something of a
mystery bird whose behavior, migratory patterns, and even numbers are
largely unknown. For birders it’s a highly prized because so reclusive
And, just for the record, it’s arguably the cutest bird in the world.
This fall the naturalists at Indiana Dunes State Park (IDSP) inaugurated a
Saw-whet Owl banding operation, only the fourth such station in Indiana, in
the hope of adding data to ornithologists’ slim store of information about
“It’s a bird we know so little about,” IDSP Chief Interpretive Naturalist
Brad Bumgardner says. “We don’t know how far south they go, they’re such a
secretive bird. We don’t know the ranges of their breeding and non-breeding
grounds. And it wasn’t until we started banding them that we began to learn
even a little about their habits and how many there are.”
Of the eight owls commonly or uncommonly seen in Indiana, the Saw-whet is by
far the smallest, about the size of a fist. Around 95 percent of its diet is
comprised of small mammals, usually Deer or White-footed Mouse. It doesn’t
hoot but rather gives a series of short whistles and very occasionally a
rasp like the sound of a saw being whetted. The field guides describe it as
tame and easily approachable (once it’s been located) but in fact,
Bumgardner says, the Saw-whet’s default response to danger is simply to
Until seven years ago, no one had any idea how many Saw-whets were migrating
through Indiana in any given year. The entire birding community might
stumble across only a handful or two in a season, with the presumption that
most—scores more? hundreds more?—were ghosting through the state undetected.
In 2002, however, Ross Brittain established a Saw-whet banding station in
Yellowwood State Forest near Bloomington and then in later years added two
more stations with Jess Gwynn. And the data they collected proved startling:
between ‘02 and 06’ 434 Saw-whets were banded, for an average of around 90
per year; then, in ‘07 alone, fully 447 were banded, more than in the five
prior years combined.
Turns out, every four years the rodent population spikes, with a concomitant
spike in the number of Saw-whet migrants. More owl food, more owls.
Here’s another fact gleaned from Brittain’s work: fully 80 percent of the
owls caught are females. The presumption: over the winter the males stay
close to the breeding grounds, protecting their territory, in the hope of
hooking up with the same female next year.
And another: Saw-whets are short-range fliers. Most migrating birds will
travel hundreds of miles a night. Saw-whets, only 20 to 30 miles.
The setup at IDSP works like this. Once it’s dark Bumgardner and his team
rig a series of three virtually invisible mist nets—30 feet long and 12 to
15 feet high—in a thickly understoried woodland near Tremont Shelter, then
play a recording of a Saw-whet’s calling at 110 decibels. Every hour,
sometimes into the early morning, they check the nets. A Saw-whet which
lands in a net won’t be injured but Bumgardner needs to be vigilant and
punctual anyway because a Barred Owl would cheerfully steal a meal if given
After catching a Saw-whet, the team measures it, sexes it (if possible),
attaches an individually numbered identifying band to its leg, then releases
Unfortunately, after several weeks of late nights at Tremont Shelter, the
banders at IDSP succeeded in catching only 19 Saw-whets: a disappointing
number but nevertheless much higher than the six banded by Brittain
Why the drop from previous years?
Bumgardner attributes it largely to the weather: 19 of 31 days in October
saw measurable rainfall, while early November was brightly moon-lit. Chances
are, he suspects, a lot of Saw-whets haven’t even left their breeding
grounds in Canada and Michigan yet. “It looks like a lot are being held up
north, bottled up, waiting for clear weather.”
Still, Bumgardner has culled some intriguing data from those 19 owls (15
female, two male, and two unsexed).
For one thing, nearly all of the Saw-whets were caught before 10 p.m.,
leading Bumgardner to suppose that they had actually flown Lake Michigan the
night before, had roosted somewhere in the park during the day, and were
only just becoming active in the early evening.
More intriguingly, though, nearly every one of the Saw-whets was caught on a
clear night with light winds, leading credence, Bumgardner says, to the
theory that this particular species is a “celestial migrant,” which is to
say that, like certain other birds, it uses the constellations to migrate.
“They may orient themselves by star patterns, not as we know them, of
course, but as they see them. And they tend not to fly on a given night if
the star patterns are obscured by cloud cover.”
So rare is the Saw-whet, Bumgardner noted, that these 19 represent
fully 25 percent of all Saw-whets ever reported along the lakefront,
according to local birder Ken Brock’s voluminous database.
Bumgardner has not yet heard of one of the IDSP Saw-whets being caught
elsewhere by another banding operation. But one of his 19 had been
previously banded in Stevens Point, Wis., while another—a female—actually
ended up in the banders’ nets at IDSP three times, the second and third time
fully two weeks after it was first caught.
For the record, virtually every one of the 19 birds was officially adopted
by a member of the public, who were invited to participate on several nights
of the operation. For $25—which will go to support further banding
operations—a person receives a detailed letter and certificate about the
specific owl and will be notified whenever and wherever it’s netted again.
The operation is being partially funded by the Northwest Indiana Migratory
Bird Association (NIMBA), and Bumgardner says that NIMBA is considering a
spring banding operation as well, in mid-March through mid-April, to
supplement the almost total lack of data on Saw-whets’ flight to their
summer breeding grounds.
“For me the
banding operation is a dream come true,” Bumgardner said. “I’ve grown up