Tracking the Elusive Saw-whet Owl

By Susan Guynn
LAMB’S KNOLL, SOUTH MOUNTAIN, MD–The nets were up, but so was the wind. Gusting at 15 to 20 mph, Steve Huy expected this to be a slow night.
Clear skies and gentle northerly winds are best for migration and netting Saw-whet Owls, he said.

“They have a light wing loading so they can carry prey,” he said. But in gusty winds that wingspan to body ratio can cause them to be tossed around and tends to keep them grounded.

Huy is a volunteer with Project Owlnet, a network of Northern Saw-whet banding stations across North America, with banders in Maryland, Pennsylvania, Michigan, Wisconsin, Maine and Canada, among other places. “(Saw-whets have) been documented as far south as Florida,” he said. “We don’t know where they all go in winter.” Saw-whets migrate from northern boreal forest breeding grounds to places more hospitable for wintering.

This is Huy’s 12th migration season at the banding station, where he spends most nights from mid-October to the end of November. He chose this ridgetop site because he wanted to be at an “altitude among the owls” and for its good roosting habitat.

“I don’t consider myself a birder, but migration fascinates me, plus I’m really interested in raptors,” said Huy, who is also a falconer. He works for Marriott International’s risk finance department in Washington, DC, and lives in Frederick, MD.

This has been an exceptionally good year for Saw-whets. An irruption, or abrupt population increase, is setting records at banding stations across the country. On a recent Sunday evening, Huy netted and released 73 Saw-whets, a record for one night in Maryland. The next night he caught 26. So far, he’s caught 179 Saw-whets and expects to surpass the typical season total of about 200.

“There was a good mast production in Canada last year. That means the rodent population did good, and so did the seeds,” explained Huy. So, in breeding season there was plenty of food for Saw-whets, which feed heavily on rodents, insects and songbirds.

Based on data collected, the Saw-whet population has a two-year cycle, alternating between good and bad years. On a down-cycle year, Huy may catch about 40 Saw-whets; up to 200 on an up year. “Chances are we’ll band 400 owls this year,” he said.

Every four years there’s an irruption. The last was in 1999. The year 2003 should have been an explosive year for Saw-whets, but Huy says it wasn’t in the East, likely due to West Nile Virus which may have affected the young of the year.

“It kept the numbers down, but we still caught more than normal, and more adults than young,” he said. Typically, he nets more young than adults and more females than males. “We don’t know if it’s a bias toward the call or if the males are not migrating as much as females,” said Huy.

Saw-whet banders play a repeating “toot, toot, toot” lure tape on nights they raise their nets. Exactly what the lure call means to a Saw-whet is not yet understood. “(Saw-whets) also do wails, whines, twitters, chirps and clicking sounds with their beaks,” said Huy. On calm nights, he can hear them. The “toot” call may be attractive to females, but not to males. “But prior to using the lure (which started in the ’80s), even then we caught more females,” said Huy.

Or, he said, males may be more inclined to stay behind and protect their nesting territory. Northern banding stations tend to catch more males. “They’re smaller than females, are more agile and able to catch birds,” said Huy. When the north lands are deep in snow and rodents hard to catch for the tiny Saw-whets, the more agile males may be feeding on chickadees and kinglets. “We don’t know for sure. We keep learning more questions,” said Huy. “Basically, all we know is how little we do know.”

  • The tiny Saw-whet, the smallest owl in the East, is the only migratory owl. Until the early 1900s, Saw-whets were believed to be permanent residents in their nesting areas, like most other owls.
  • “We don’t think the whole population is migratory, but most do,” said Huy.
  • They are secretive and nocturnal, and few people actually see them. Birding groups visit Huy’s station just to add the elusive owl to their life list, he said.
  • Saw-whet plumage is rusty to chocolate brown, streaked and speckled with white; their eyes golden yellow with large black pupils; and when most people see one for the first time all they can say is, “Awwwww, it’s so cute!”
  • They’re about 7 inches tall and weigh around 3 ounces, about the same as a robin. Fluffy feathers all the way down to their talons make them appear larger, as does their 18-inch wingspan. Their size makes them vulnerable to predators, including larger owls.
  • “An interesting thing that’s turned up this year (at some other banding stations) are ‘blonde’ Saw-whets,” said Huy. Their feathers are lighter than is typical.

Waiting for Saw-whets
Each night during migration, Huy raises seven 40-ft. long by 10-ft. high nets. Most run east-to west along an abandoned section of the Appalachian Trail. Shorter lengths run north to south. Each net has four panels with deep pouches. He checks the nets every hour. Over the years he’s caught a few Screech Owls and young Barred Owls, an occasional Flying Squirrel and one Red Bat. When a Saw-whet flies into the net, it drops into a pouch where it usually remains calm and quiet until Huy or one of his helpers comes to remove it.

“Some (Saw-whets) play dead. Others try to tear you apart,” said Huy. Once out of the net, he places the owl in a small mesh lingerie laundry bag. The first net check on this night, around 9:40 p.m., yielded two Saw-whets. Tucked into the bags, he took them back to a small wood shed and recorded pertinent data–weight, wing and beak measurements, fat deposits, wing feather color (to help determine age, along with weight) — and applied a small numbered leg band.

The first owl, docile and calm, was taken from the bag and slid head first into a 6-ounce Donald Duck juice can. “It immobilizes them so I can weigh them and band them,” explained Huy. The bands are provided free. The 12×12 banding shed was built last year through funding from a private grant and is on Maryland Department of Natural Resources’ property, but Project Owlnet is not a DNR program. The Maryland Ornithological Society provided funds to replace Huy’s 10-year-old nets, he said.

“Ninety-three grams. This is a female,” said Huy, who then attached a leg band to the owl. In and out of the can, the owl remained calm and unflappable.

Saw-whets have yellow eyes and the darker the yellow the older the owl. But Huy said he’s finding that doesn’t always hold true. The banders use a simple color guide, comprised of a strip of paint color chips, with each assigned a number for data purposes.

Huy then checked the owl’s skin for fat deposits by gently blowing to separate its downy feathers. “A fat deposit on a wingpit, in particular, will be yellowish,” he said. Fat indicates the owl has been feeding and sitting, instead of flying.

He then studied its wing molt patterns. First-year birds (hatched this year) have evenly colored (flight) feathers. In their second year, they start to molt and new feathers appear darker than first-year feathers. He holds the wing in the glow of a black light, which makes a chemical found in new feathers appear a raspberry color. Older feathers have a blue hue.

Another owl weighed just 80 grams–a little heavy for a male, a little light for a female. After completing his measurements, Huy determined it was an emaciated female.

Shortly after midnight, he retrieved the last two birds of the night, a total of six, and lowered the nets.

He was right. It was a slow night. But for now, there’s always tomorrow.

  • Saw-whets at a glance:
    Saw-whets are the smallest owls
    in eastern North America.
  • They’re about the size of a robin, but appear larger because of their fluffy feathers.
  • Saw-whets are nocturnal and have exceptionally well-developed hearing and vision. They prefer mice, voles, shrews and occasionally small songbirds.
  • Few people ever see a Saw-whet Owl.
  • Clutch size depends on the mouse population. If the prey density is low, a clutch may be three to five eggs; six to eight eggs if it’s high. They nest in tree cavities.
  • Saw-whets are ready to leave the nest in 35 to 40 days.–Frederick News-Post