Friday, October 30, 2009

Esmeralda and her food

I don't have too much time before I need to get some sleep but I wanted to post this picture of our newest owl with a transmitter, Esmeralda. She saved our night of tracking last night because we were able to track her from our cars when the weather turned sour and it started misting heavily and then raining. The other saw-whet we are following, Isra, hangs out in the area south of the King's Gap banding station and is quite impossible to track from a car.

Esmerelda 103009
Esmeralda, a female Northern Saw-whet Owl

Esmeralda is a second year female, if I remember correctly, and she is holding some prey item in her talons in the photo above. Leave a comment if you think you can help us out by identifying it.

Thursday, October 29, 2009

Wet, wet, wet - dry! - wet, wet...

The weather's really been against us this season, as one wet system after another has squatted over the Northeast. This has been especially true for weekends, meaning that most of the groups scheduled to visit the banding stations have either had to cancel, or sit through damp, owless evenings.

We have had some bright spots. Last Sunday night, Oct. 25, conditions were nearly perfect. A cold front had passed through the night before with wind, rain and a lot of falling leaves, but the 25th was cold and calm, with only a half-moon's worth of light. I was running our Hidden Valley site, and after empty nets at the first check, the owls started coming fast and furious, seven or eight at a time. By the time we closed up at 2:30 a.m. we had 24 new saw-whets. In all, we're at about 150 owls for the season - a slow start that puts us behind the average count for this date.

One of the most exciting aspects of our work is the capture of an owl that someone else banded - a foreign recap, of which we've had seven already this year. One of those was an interstation recovery from our own project, a saw-whet banded as a second-year female by Jan Getgood at her home near Hummelstown Nov. 9, 2005, and recaptured on Oct. 20 of this year at our Small Valley site - five-year-old owl, a very respectable age for a saw-whet. (The new longevity record for the species, just set this week by a saw-whet banded and recaptured in Trinity, California, is 9 years old.)

Among the other recoveries whose origins we know were owls captured at King's Gap this month originally banded in Hilliardtown Marsh, ON in 2007; Shirley's Bay, ON, last fall; and the Mohonk Preserve in southeastern New York in 2008. One owl recaptured at Small Valley was banded in Brockway, PA, by Keely Roen's Penn State group last November.

Two of our owls have likewise been reported elsewhere - a Hidden Valley bird from 2007 recaptured at Villa-Marie, Quebec, and a 2008 Hidden Valley owl at Shirley's Bay, ON.

The telemetry work has been a slow push as well for Drew, Kim and Hannah, who are doing yeoman's work under trying circumstances. The weather hasn't helped, and neither has Isra, the saw-whet we're currently tracking - an owl with a talent for leading the crew all over creation, then settling down in the one part of South Mountain designed to confound a radio signal.

Typical was the other night - no matter where Kim positioned herself, she couldn't get a good bearing on the bird, who kept moving around so that Hannah and Drew up on top of the ridge likewise had to keep shifting to new locations. Meantime, Drew was watching on his smart phone as a large area of rain was sweeping in the from southwest. About 4 a.m. it started to drizzle, but it looked from the radar as though the rain would miss them.

Not really. Instead, they found themselves in a driving downpour, slogging 20 minutes back to the car through dripping vegetation. "One of those nights," Drew said later, "but at least we got two extra hours of sleep." Ah, the glamor of wildlife research.

If you're in central Pennsylvania this weekend, be sure to join us for the annual Halloween Owls program at the Ned Smith Center, starting at 7 p.m. Saturday, Oct. 31. We'll be running nets to catch saw-whets (weather permitting), and our good friends from the Shaver's Creek Environmental Education Center will be there with a variety of live owls. It's always fun, and very kid-friendly.

Wednesday, October 21, 2009

Too busy to write

George Gress banding a saw-whet at Hidden Valley (©Scott Weidensaul)

It feels as though we've gone from 0 to 60 around here in no time flat. After a miserable weekend Oct. 15-17, with tons of wind-driven rain, and some snow at the higher elevations, the skies cleared out Sunday, Oct. 18 and we started catching owls - 32 that night, 17 of them at Hidden Valley alone.

All three sites are attaching geolocators, and we've deployed about 30 of the 190 we need to send out this fall. And we've radio-tagged two more saw-whets, which the crew nicknamed Elvira (a hatching-year female) and Isra (a second-year female). Xena, which was tagged Oct. 12, seems to have left the area, but Skreech the screech-owl remains on its territory near King's Gap.

Thank goodness for Skreech. Last weekend, as the worst of the weather was descending, our colleagues Nick and Mary Freeman, who study breeding owls (including saw-whets) in the mountains around Los Angeles, flew in from California. Their first night of banding was canceled due to rain, and Saturday night we were determined to get them out for radio-tracking - except that Xena had bugged out in the rain the night before.

So it was Skreech to the rescue. For three hours in clammy mist and occasionally heavy rain, we gave Mary and Nick a tutorial in basic radio triangulation techniques, along with tips on getting your data sheets soaked, holding dual umbrellas to shield the tracker, and avoiding drips of icy, barely-above-freezing rain down the back of your neck. Mary asked, "Is Pennsylvania always butt-freezing cold?" At this time of the year, often.

Fortunately, they were still in town the next day when the skies cleared and north winds began to blow. They had a few great hours of hawkwatching at Waggoner's Gap, then joined us at Hidden Valley for our 17-bird night.

Since then, the weather has grown considerably less butt-freezing, and with Indian summer, not surprisingly the number of owls has dropped off, down to five to eight per site each night. Still, we're up to 75 for the season - below average but making up ground rapidly.

Tuesday night the telemetry crew were chasing Isra up in Michaux State Forest. Between the canopies of the trees, they could see patches of star-splashed sky - and the whizzing, bright trails of the Orionid meteor shower, which graced the final hours of the night before they put Isra to bed, and went off to get some sleep themselves.

Friday, October 16, 2009


Although a big nor'easter storm has temporarily shut us down, we had an exciting couple of nights before the rain and snow hit. Drew, Kim and Hannah have been tracking Xena and Skreech as they hunt the woods near King's Gap. On the banding side, while the number of owls remains quite low for this time of year - just 10 saw-whets and two eastern screech-owls - we've begun deploying the light-sensitive geolocators we're using this season to study their migration.

A light-sensitive geolocator, which weighs about 2.5g (©Scott Weidensaul)

The geolocators are miniature, backpack-mounted data-loggers, continuously monitoring light levels for up to two years, from which we can determine the rough latitude and longitude of the migrating owl. The tiny units are custom built by the British Antarctic Survey, and have been used to study the migrations of wood thrushes and purple martins, but never saw-whet owls.

This week we began fitting saw-whets with geolocators at our Hidden Valley station, and will soon be doing so at all three of our sites. The harness is made from thin, tough Teflon ribbon that figure-eights around the bird's body, holding the geolocator high in the middle of the back. A short stalk sticks up above the feathers, with the light sensor at the tip. The entire unit and stalk are encased in a light, thin shell of epoxy to protect the innards from sharp owl beaks.

A saw-whet, fitted with a geolocator and ready to go. The sensor stalk protrudes an inch or so above the feathers on the back, continuously recording daylight and darkness. (©Scott Weidensaul)

(A special thanks to Marge Gibson and her staff at the Raptor Education Group in Wisconsin, who tested the geolocators and the harnesses on three of their captive saw-whets, even going so far as to create nest boxes with natural flicker- and pileated woodpecker-sized entrance holes, to make sure the sensor stalks didn't interfere with the owls' ability to enter and exit the cavities.)

We were also grateful to York University grad students Maggie McPherson and Callie Stanley for giving up their (Canadian) Thanksgiving holiday to come south to help with the work, and to give us the benefit of their geolocator experience working with thrushes and martins under Dr. Bridget Stuchbury.

From left: Callie Stanley, bander Nate McKelvie (front), Maggie McPherson, Pat Trego (rear), Nada Farah, Baha' Ishaq (rear), Ika Rani Suciharjo and Maria del Mar Contaldi. (©Scott Weidensaul)

Finally, we were delighted this week to welcome a number of the international interns from Hawk Mountain Sanctuary, which is not far from Hidden Valley. Marie del Mar Contaldi from Argentina is working on a master's on vulture and condor biology; Nada Farah from Lebanon serves as the country's Important Bird Areas coordinator; Baha' Ishaq from Palestine is an undergrad at Bethlehem University and the only licensed ringer (bander) in the Palestinian territories; and Ika Rani Suciharjo from Indonesia is a high school biology teacher with extensive experience in environmental conservation. As you can see from the picture, they were thrilled with their first encounters with saw-whets.

Tuesday, October 13, 2009

Xena, visitors, and better things to come

Well, things are started to click along down here, slowly but surely - and it appears the flood gates have finally opened to our north, promising better owling to come.

Although we only caught two saw-whets Monday night - one at Small Valley and one at King's Gap - the latter bird, an immature female, left with a radio transmitter and a nickname that intern Hannah Panci came up with - Xena, for the TV warrior princess, in recognition of this little fighter's spirit. From her release until about 3 a.m., Xena stayed on the ridgetop near the banding station, then moved down the west side of the mountain, staying put until the tracking crew left her at 7:30 a.m.

Although we didn't have any owls at Hidden Valley, we did have a couple of interesting guests, who will be with us all week. Maggie McPherson and Calandra (Callie) Stanley are grad students at York University in Toronto, studying with Dr. Bridget Stuchbury, a specialist in songbird migration, and one of the first scientists to use geolocators like the ones we'll be deploying this fall.

Maggie and Callie are both working with wood thrushes and purple martins at Bridget's study site in northwestern Pennsylvania, and Callie is also tagging thrushes on their wintering grounds in Costa Rica. They've given up their fall break to drive down from Toronto and spend the week helping us with our geolocator work - and spend some time with owls, since Maggie began banding NSWOs in ninth grade in Ontario, working the Timiskaming stations run by Bruce Murphy.

Speaking of whom, Bruce posted a happy warning to those of us to the south that the wait may soon be over. Friday night they had 95 saw-whets, one of their biggest nights ever, although high winds have cut their catch rate since then. They're up to 390 for the season, and he thinks we in the south will have the roughly average flight I've been expecting this year, which for our sites would mean around 450-500 owls.

Saturday, October 10, 2009

Slow going

The banding stations have been open for a week, but in that time we've netted just a single saw-whet, caught Oct. 5 at our Hidden Valley site - one of the slowest starts we've had in the 13 years we've been studying owl migration.

Part of the reason may lay with the relatively mild, windy, showery weather we've had here in the mid-Atlantic, but I suspect even more of the problem lies to our north - a series of storms that have paraded across southeastern Canada, slowing down the migration.

However, there's a dramatic change in the weather coming over the next few days, with an Arctic air mass plunging down through the Great Lakes and East, with predictions of snow downwind of the lakes and on the higher elevations of New England. We're expecting this cold snap to generate the first good push of owls in our region, perhaps as early as tonight.

Meantime, our radio-telemetry crew has been focusing its attention on the screech-owl we tagged last month, and they're taking a weekend off after six nights of triangulation. Skreech, as they nicknamed the bird, has been hunting the western side of King's Gap State Park and adjacent portions of Michaux State Forest, moving around frequently enough to keep Drew, Hannah and Kim on their toes. Once we start getting saw-whets, they'll switch their attention to them, but we'll continue to keep track of Skreech in the weeks ahead, too.

Monday, October 5, 2009

Skreech and the full moon

"Skreech," the first of this year's owls to be radio-tagged. (©Hannah Panci)

Poets, lovers and songwriters like full moons. Owl researchers, not so much.

For whatever reason, the number of owls caught drops dramatically during a full-moon period, which may explain (along with the lovely, mild weather) why we're 0 for 4 with saw-whets - having opened our 2009 banding operation four nights ago, we still have yet to net our first saw-whet owl.

This isn't unusual - it's often pretty slow the first week of the season, and the migration doesn't peak until about Halloween. In each case, though, the crews at our three sites had plenty to divert to their attention, even in the absence of owls. At Hidden Valley Saturday night there was a fireworks display in the valley, while at Small Valley (where the caretaker has been seeing three large black bears) the volunteers were just glad nothing went bump in the night.

At King's Gap, we actually did catch an owl last week - not a saw-whet, but I'll let Hannah Panci, one of our research interns, pick up the story:

"Meet our red-morph eastern screech-owl (a hatch-year bird, sex unknown), given a gangster name of “Skreech.” After many tries over the course of three nights, Scott, Drew, Kim and I managed to lure it into the net last Wednesday night. Fitted with the newest model of radio transmitter backpack, it was released, and our little research team tracked it until 3 am. We found it again yesterday, sneakily roosting in the open about 30 feet off the ground. We’ll be tracking Skreech throughout the fall, both as telemetry practice and to see how its movements may affect any tagged saw-whets we are following. So look for more updates!"

That's Hannah's photo of Skreech, which we aged as a hatching-year bird - meaning it was born earlier this year, and is entering its first winter - by looking at its feather molt, and the pattern of pale scalloped markings on its primary wing coverts, among other clues. Unlike the migratory saw-whets, we're expecting Skreech to stay fairly close to its banding site on top of South Mountain, although as a young bird, it may still be drifting about, trying to establish a permanent territory. Once it does, though, the bird should sink down roots and stay put for the rest of its life.