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A Grassroots Banding Venture Reveals How Wonderful Northern Noticed-whet Owls Are  A Grassroots Banding Venture Reveals How Wonderful Northern Noticed-whet Owls Are SawWhet FI

A Grassroots Banding Venture Reveals How Wonderful Northern Noticed-whet Owls Are

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There’s something fantastic about an autumn night time; the sharp chew to the air, the rustle of a north wind within the final leaves clinging to the tops of the oaks, Orion shining in a moonless sky over the central Appalachian ridges of Pennsylvania—and echoing over all of it, a repetitive, me­chanical beep that reminds most individuals of the warning alarm when a rubbish truck is backing up.

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That sound—on this case, an audio recording performed by way of a pair of bullhorn audio system—isn’t automotive. As a substitute, it’s the toot-toot-toot name of a Northern Noticed-whet Owl, the male’s breeding track that’s utilized by scientists to lure migrating saw-whets out of the star-shot sky and into mist nets. I’ve spent near a thousand autumn nights like this over the previous twenty years, in my work as a researcher capturing and finding out this mysterious little bundle of feathers. But as I climb the decrease slope of the ridge that results in our nets, I’m nonetheless as excited as I used to be again within the 1990s, embarking on our research of the unseen night migrations of those most enig­matic raptors in North America.
One factor’s for positive, the hill hasn’t gotten any much less steep previously 23 years. However my companions and I don’t wait to catch our breath; shining our headlamps down alongside the road of nets, I can see three—no, 4—small, gray-brown our bodies cradled and wriggling within the mesh, and sure extra across the nook the place the remaining array types an L form. Somebody flips a change to show off the audio play­again, and the night time goes silent as I attain fastidiously into the online and grasp the small, totally feathered ft of the owl to maintain its needlelike talons out of my fingers. In just a few moments I’ve slipped the owl free from the mesh.
The tiny owls are wrapped up in fabric baggage to maintain them calm till it’s time for researchers to conduct a short examination. Photographs by Chris LinderA saw-whet is prepared for a fast examination when researchers will gather information and affix an figuring out leg band.
Solely the scale of a soda can, a saw-whet is a diminutive raptor, however don’t mistake its wee measurement for a scarcity of moxie. This fowl has fluffed out its feathers in a bid to intimidate the enormous primate holding it, and is quickly clacking its invoice in a dead-seri­ous risk as I slip the little owl into a light-weight cotton bag and cinch the drawstring tight. The owl snaps its beak as soon as once more and I look all the way down to see the information of eight sharp, shiny black talons poking by way of the fabric as I transfer to the following fowl.
By the point we head again down the hill to just a little cabin, we have now 9 freshly caught saw-whets in fabric baggage. The birds have to be weighed, measured, sampled for blood and feather evaluation, and outfitted with tiny metallic leg bands—the newest additions to a continental monitoring effort that has solved some (however not at all all) of the mysteries surrounding this tiny fowl of prey.
A Northern Noticed-whet Owl is gently extracted from a mist internet at an Appalachian science analysis station in Pennsylvania. Photograph by Chris Linder.
A Mysterious Little Owl Dropped at Gentle
My first encounter with saw-whets within the hand got here in 1996. The earlier autumn Eric Atkinson—on the time a biologist at Hawk Mountain Sanctuary close to my dwelling in japanese Pennsylvania—had banded a surprising 80 saw-whets in his rural yard with the assistance of his spouse Melonie. They have been attempting what was then a reasonably new method utilizing an audiolure recording, and their 80 owls in a single season astounded anybody who thought of saw-whets extremely uncommon—which was nearly everybody.
Within the mid-1990s, saw-whets have been listed as a candidate species for state safety in Pennsylvania, a fowl so sometimes seen that even essentially the most avid birders I knew may go a lifetime with out recognizing one. So I used to be each shocked and really intrigued by the Atkinsons’ outcomes. On the time, my consuming ardour was banding hawks, falcons, and eagles on migration by way of the Appalachians—raptors that have been trapped through the day. However I’d felt the primary, seductive tug from the Darkish Aspect with the Atkinsons on these autumn nights at Hawk Mountain, and after catching a number of saw-whets myself, I used to be hooked. By the following 12 months, with some seed cash from a small state grant, we had recruited a unfastened community of banding stations throughout Pennsylvania to focus on saw-whets.

Volunteer Emily Case assembles a mist internet to organize for the approaching night time of monitoring the saw-whet migration at a Ned Smith Heart station in Pennsylvania. In a given 12 months, greater than 100 volunteers help with the middle’s saw-whet banding operation. Photograph by Chris Linder.
The place to Search for Noticed-Whets
Ask a birder the place to discover a saw-whet, and also you’ll be directed to look in thick conifers. However our monitoring of radio-tagged owls over the previous decade to doc their daytime roosting habits in autumn and winter discovered them in nearly any type of shelter, so long as it supplied tangled safety—pines and hemlocks, dense stands of mountain laurel and rhododendron, previous blowdowns, and honeysuckle snarls.
Earlier than the leaves drop in autumn, the most typical roost websites have been excessive within the outer branches of huge deciduous bushes, hidden in clumps of leaves the place mobbing songbirds have been unlikely to search out them. The identical owl may roost in the future instantly on the bottom in a rhododendron thicket, and the following day 80 ft up in a pitch pine. (And talking from private expertise, when you suppose “warbler neck” is unhealthy, strive “owl neck”—the crick a researcher will get from peering straight up by way of binoculars for an hour or extra, looking for a fist-sized owl in a excessive pine tree filled with a whole bunch of huge cones.)
Be taught extra about Northern Noticed-whet Owls in All About Birds.

I oversaw a type of first stations for the Ned Smith Heart for Nature and Artwork, and that effort, now in its 23rd 12 months of netting these little nighttime owls in central Pennsylvania, has grow to be one of many largest saw-whet analysis applications in North America. With a crew of 20 federally licensed banders and a complete crew of practically 100 folks—all of us volunteers—working at three analysis websites, the Ned Smith Heart stations have banded greater than 12,000 owls and pioneered using a lot of new applied sciences, together with geolocators and nanotags, to check owl migration. Each rainless night time from the start of October till after Thanksgiving we’re within the woods, stretching our nets into the midnight hours and enjoying that repetitive, garbage-truck name.
The fowl on the coronary heart of all this effort continues to be enthralling, however much less of a cipher than it was twenty years in the past (and now not listed as a candidate species in Pennsylvania, partly due to our work documenting it).
The Northern Noticed-whet Owl is the smallest raptor in japanese North Amer­ica. In our research, bigger females aver­aged about 96 grams, just a little greater than half the burden of an Jap Screech-Owl and a bit lower than an American Kestrel. Male saw-whets solely averaged about 78 grams, however we don’t see many males.
One of many abiding puzzles about these birds is the dramatically skewed intercourse ratio at banding stations throughout their vary, the place females outnumber males three or 4 to 1. Virtually the entire males which can be caught are juveniles making their first migration. Out of 12,000 or so saw-whets we’ve banded in Pennsylvania, solely a few dozen—actually one in a thousand—have been totally grownup males.
The place are the grown-up guys? There’s little doubt that our pattern is biased to a point as a result of our audiolure is a male courtship name, which ought to be extra enticing to females. (Although why feminine owls are interested in a breeding name in autumn stays a puzzle.) Current work by our colleagues Chris Neri and Nova Mackentley at Whitefish Level Chook Observatory in Michigan discovered that enjoying a feminine vocalization at one set of nets elevated the male seize price there; however additionally they discovered that females nonetheless dominate the sampled saw-whet migration general.
A feminine bias in saw-whet migration might be defined by trying to Scan­dinavia. There, research of the saw-whet’s closest relative, the Boreal Owl (or Teng­malm’s Owl, because it’s identified in Europe), have documented grownup males stay­ing of their northern breeding vary by way of the winter. Maybe (as with Boreal Owls) male saw-whet owls transfer extensively and considerably nomadically to search out areas with excessive rodent populations, to allow them to set up territories and be prepared when the females come again north. However to date this habits stays a speculation awaiting affirmation.
A saw-whet owl is examined after being faraway from a internet. Photograph by Chris Linder.
Nomadic Sojourners
The creator enthralls a faculty group by introducing them to a Northern Noticed-whet Owl. All images by Chris Linder.Through the years, kids impressed by saw-whets on the Ned Smith Heart analysis stations have grown as much as grow to be scientists main analysis in local weather research and ornithology. Researchers and volunteers are educated to shortly and delicately extract saw-whets from mist nets.The beak size is measured through the examination. A part of the bodily examination consists of noting the yellowness of the eyes by comparability with a housepaint colour palette from a ironmongery store.UV black lights reveal the presence of fluorescent pigments that assist decide the owl’s age. See sidebar beneath for extra.PreviousNext
Noticed-whets are oddball birds, onerous to pigeonhole in a lot of respects. Their migrations are extremely cyclical, with hordes coming south each three to 5 years, however far fewer at different instances. Many birders, and various ornithologists, check with saw-whets as irruptive, however they don’t match the traditional definition; their migrations are common, and whereas the variety of adults we catch every fall fluctuates a bit from 12 months to 12 months, it’s pretty secure over time.
An enormous flight 12 months is sort of solely the results of an enormous inflow of juveniles into the inhabitants. The children, in flip, are the product of inhabitants spikes in small rodents within the northern U.S. and Canada (particularly red-backed voles, a favourite prey of this raptor), which comply with autumns when the spruce and fir bushes within the boreal forest groan underneath heavy cone crops.
We are able to make a fairly good guess in regards to the magnitude of subsequent 12 months’s owl flight by trying on the measurement of this au­tumn’s boreal cone crop. Plenty of cones means plenty of seeds (rodent meals), and if there are many rodents, saw-whets reply by laying massive clutches of eggs, as much as 9 in a nest. Some females handle to provide two clutches of eggs in two nests, with two completely different males, in a single season. These are the growth years—like 1995, 1999, 2007, and 2012 within the Northeast—once we’ll catch practically a thousand owls at our three saw-whet banding websites in central Pennsylvania, three-quarters of them juveniles. In a standard 12 months, we’ll catch solely a pair hundred largely grownup saw-whets.

UV or “black” lights reveal the presence of fluorescent porphyrin pigments in saw-whet wing feathers, which will be measured to find out the owl’s age. Photograph by Chris Linder.
Glow-in-the-Darkish Owls
Once we catch an owl, one of many first duties is to evaluate its age, which we do by analyzing its flight feathers. Banders search for put on and fading to tell apart previous from new feathers, the sample of which adjustments with the fowl’s age. However such put on will be delicate and onerous to see.
Owl banders, although, have a secret weapon—owls fluoresce within the presence of ultraviolet gentle. Flick on a UV black gentle and the undersides of the flight feathers on nearly all owls glow a superb neon raspberry, the results of porphyrins, a category of pigments that many birds use to paint their eggs, however that owls (and a dozen or so different orders of birds like nightjars and bustards) add to their feathers. Because the feather ages the porphyrins break down, so the older the feather, the much less brightly it fluoresces.
Open the wing of a newly caught autumn saw-whet, shine a UV flashlight on the underside of its wing (being cautious to keep away from the fowl’s eyes) and you might even see that the outermost three or 4 primaries, and innermost two or three secondaries, fluoresce brilliantly, whereas the feathers in the midst of the wing are a lot duller. That’s a second-year fowl, born the earlier 12 months and starting to exchange its juvenal flight feathers with brilliantly fluorescing new ones. An owl on its first migration, just some months previous, would have a pleasant, even purple glow throughout all of its wing feathers, that are the identical age.
Not solely is that this cool and helpful science, the sight of a glow-in-the-dark owl is a assured show-stopper when we have now guests, and another instance of how stunning the world of nocturnal migration will be.

Whereas most migratory fowl species present sturdy loyalty to their breeding and wintering places (I’m reminded of the banded Cerulean Warbler that overwintered in the identical nook of the identical shade-coffee farm in Colombia 5 years in a row), that’s not the case with saw-whets. One owl we tagged with a geolocator wintered some years as far south as western Virginia, and different years near the Canada–New York border. Some years this feminine migrated into Quebec to breed, however in others she remained within the mid-Atlantic states. Though a broader evaluation of saw-whet banding recoveries throughout their migratory vary confirmed that these owls have a tendency to stay to regional flyways, our analysis has con­firmed how nomadic a few of these tiny sojourners will be inside these bounds.
Whereas the science has clearly been attention-grabbing, the human aspect of our venture has had its personal rewards. It’s been an important instance of extremely profitable citizen science. Maybe not surprisingly, our crew of banders consists of some professional­fessional wildlife biologists whose day jobs are with state businesses or environ­psychological nonprofits—nevertheless it additionally features a union plumber, a machinist, lively and retired highschool lecturers, a regulation professor, an environmental educator, and an data programs supervisor. We’ve hosted school interns from Penn State College, and once in a while we’ve introduced children as younger as 11 (and their mother and father) onto the crew, with terrific re­sults. A number of of our youngest saw-whet crew members have gone on to nice careers; one is conducting postdoctoral analysis in local weather science, and others have grow to be famous birding guides and discipline ornithologists.
I usually check with saw-whets as a gateway drug for conservation, as a result of they’re, in any case, the proper combina­tion of a ferocious predator in a small, nonthreatening package deal—cute and cuddly to the human eye, however with all of the gravitas of the most important carnivore. Through the years we’ve hosted hundreds of individuals at our banding stations, from Cub Scout packs to college lessons, and I’ve but to come across a single particular person, regardless of how disconnected they might be from the pure world, who doesn’t really feel an electrical jolt the primary time they meet the extent stare of these yellow eyes. For a lot of such guests, that have is life-changing.
The Ned Smith Heart, just a little cabin deep within the woods in central Pennsylvania. Photograph by Chris Linder.
A Grassroots Banding Effort that Spans North America
Our banding stations usually are not alone on this effort to grasp saw-whet migration. We’re a part of a continental effort generally known as Venture Owlnet, with greater than 125 companion stations throughout Canada, the U.S., and Mexico, all utilizing comparable protocols and sharing information and outcomes. Due to this dense community of owl-banding stations, particularly within the Northeast and Nice Lakes, we routinely internet saw-whets in Pennsylvania which have already been outfitted with leg bands—birds that have been initially banded as far afield as central Wisconsin, the Bruce Peninsula on Lake Superior in Ontario, or the shores of the St. Lawrence River in Quebec. In all, we’ve captured practically 500 owls beforehand banded at different stations. We’ve additionally had greater than 250 of our Pennsylvania-banded birds re­captured at different places—together with one feminine saw-whet present in a nest field in western Quebec, paired up with a male saw-whet that had been banded at a Venture Owlnet website in Michigan. Each birds had flown 600 miles, from reverse instructions, to Quebec to search out one another.
How far south saw-whets migrate is an open query. They’re so secre­tive that, absent focused mist-netting analysis of the type we undertake, it’s simple to overlook them fully. Over 43 years courting again to 1961, Alabama had solely seven accepted data of Northern Noticed-whet Owls. However after I satisfied a few mates close to Birmingham to arrange an audiolure sta­tion at their dwelling in 2007, they started catching saw-whets often. Alabama now has a whole bunch of saw-whet data from a lot of banding stations. Researchers have equally found migrating saw-whets in different areas the place the species had beforehand been thought of uncommon or absent, reminiscent of Ar­kansas. Within the West, the place saw-whets breed in mountainous terrain all the best way into central Mexico, the migration sample has been a lot more durable to as­sess, however of us are attempting.
Tiny Brown Treasures With Sensible Yellow Eyes
Northern Noticed-whet Owls are extra frequent and widespread than anybody suspected just a few many years in the past, however there may be trigger for concern: a lot of their breeding vary lies throughout the southern boreal forest, the place industrial logging is the dominant drive on the panorama. Photograph by Chris Linder.
I verify my watch. It’s time for one more internet verify, and with the earlier batch of owls banded and returned to the woods, my crew and I hike again up the hill by way of the night time, the sound of the audiolure getting louder in our ears with each step. The main points range from website to website, however every year for 23 years we’ve run the identical variety of nets in the identical places for a similar variety of nights for that two-month interval in October and November, in what’s generally known as constant-effort mist-netting. Every year’s information, added to these of the previous, enable us to ask questions on points like inhabitants developments that we couldn’t earlier than. And each season’s new information make what we’ve collected in earlier years more and more useful.
Proper now we’re tackling the formi­dable job of analyzing three many years’ price of seize information from Venture Owlnet banding websites throughout the east­ern U.S. and Canada to see what the numbers can inform us about how the general saw-whet inhabitants is faring within the early 21st century. Northern Noticed-whet Owls are much more frequent and widespread than anybody suspected just a few many years in the past, however there may be trigger for concern. Banding at Assateague Island in Maryland since 1991 has proven that every successive peak within the saw-whet’s ebb-and-flow cycle has been decrease than the earlier peaks. This might be only a native subject, however a lot of the saw-whet’s breeding vary lies throughout the southern boreal forest, the place industrial logging is the dominant drive on the panorama. Some analysis suggests these small owls have a more durable time efficiently feeding their chicks in fragmented forests, and our long-term migration information might present us whether or not they’re sustaining their numbers within the face of such strain. We’re additionally taking a look at whether or not the warming local weather is altering the timing of their migration.
We attain the highest of the hill; I’m just a little winded, however who cares? The primary internet has an owl, and I really feel the electrical cost I all the time really feel once I see these obvious yellow eyes. Glancing down the lane, I see the night time has extra small, gray-brown treasures to share, ready for us within the internet—feathered solutions to questions we’re nonetheless simply studying ask.
Scott Weidensaul has written greater than 30 books and is a codirector of Venture Owlnet. He has been finding out fowl migration of all kinds for the reason that 1980s. His latest e-book, about migration science and world migra­tory fowl conservation, might be printed in 2020 by W. W. Norton.

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