Well, the change in the weather brought a little improvement in our fortunes - along with a lot of leaves in the nets. Although Small Valley didn't catch any owls, they heard NSWO (that's the banding code for northern saw-whet owl) vocalizing in the woods. Hidden Valley had one (plus a big tear in one of the nets, courtesy of a passing mammal) while King's Gap snagged two new birds, both adult females, and both of which left with radio-transmitters.
That brings us to 15 saw-whets for the season. Last year at this time, during the huge southward irruption of saw-whets, we'd already caught 155 owls, but we're also well below our 10-year average for the date of 50 NSWOs. The warm weather really slowed things considerably, but I'm confident that will now change, since we're looking at blustery northwest winds and nighttime lows below freezing the next few nights.
It's a good thing we have two new birds with radios, because it appears Dizzy has finally flown the coop. Anna Fasoli and I got to Wolf Pond Rd. at 6 p.m., but there was no sign of her signal; we quickly walked in to the old roost site, checked, then split up and drove the middle and perimeter of the whole Haldeman Tract/Broad Mountain/Small Valley/Berry Mountain area without finding her. After Anna and I split up, she continued to track through Clark's Creek Valley and west of the Susquehanna on her way home to Carlisle, but came up empty.
Anna will be out today to locate the new owls' roost in King's Gap or Michaux State Forest, and we'll be doing daytime and nighttime tracking this weekend.
We received news this morning that another of our spring '08 owls was recaptured at a familiar place - Hopkins Memorial Forest in extreme northwestern Massachusetts, at Drew Jones' site run by Williams College. This is a that was banded March 2 at King's Gap, and is the second spring KG bird to show up at Hopkins this fall.
While I was repairing the torn net at Hidden Valley this morning, the woods were full of flocks of migrating robins, the air was full of falling maple and black gum leaves on the stiff breeze, and the sky was absolutely alive with big flocks of Canada geese. Those are all signs that we should see a change for the better in our owl numbers.
Showing posts with label Dizzy. Show all posts
Showing posts with label Dizzy. Show all posts
Friday, October 17, 2008
Wednesday, October 15, 2008
Dizzy still in area
It was another unusually warm autumn day at Weiser State Forest yesterday as I set out to locate “Dizzy,” the saw-whet we caught October 5 at Small Valley. I did not pick up her signal near the Small Valley banding station, where she roosted on October 7, so I drove northeast through the state forest towards her last known roost location.
On October 11, Scott and I located her on roost just north of Wolf Pond Road. Today, I drove past this location to a nearby vantage point. I did not pick up a signal north over the valley, so I headed back to where I came from. As a turkey ran out in front of me, I stopped the vehicle, which decreased my background noise just enough to hear the faint “beep” of Dizzy’s transmitter off in the distance through my roof antenna. I hooked up my receiver to my folding “handheld” antenna, which indicated Dizzy was southeast of me.
I found her soon after at the top of a black gum tree, just three quarters of a mile east north east of her previous roost location on October 11. I couldn’t actually see her, but her signal was localized in a raptor nest about 30 feet off the ground. Saw-whets have used similar abandoned nests for roost locations in the past, but according to Scott Weidensaul, nothing in the literature suggests this has been observed elsewhere. As I was collecting habitat data, six titmice flew in and were quite upset to find Dizzy, but did not stick around very long. This roost location is about 2.5 miles north east of the Small Valley banding station.
It will be interesting to see her roost movements in the next few days as temperatures drop, which may encourage Dizzy to continue her migration. On the other hand, Dizzy may choose to spend the entire winter in this area. We will continue to monitor her roosting activity as long as she stays in the area, and in the meantime, we will continue to patiently wait for more owls to arrive at King’s Gap. Again, last night the moon was too bright and temperatures were just too warm, and no owls were caught at any of the three sites.
On October 11, Scott and I located her on roost just north of Wolf Pond Road. Today, I drove past this location to a nearby vantage point. I did not pick up a signal north over the valley, so I headed back to where I came from. As a turkey ran out in front of me, I stopped the vehicle, which decreased my background noise just enough to hear the faint “beep” of Dizzy’s transmitter off in the distance through my roof antenna. I hooked up my receiver to my folding “handheld” antenna, which indicated Dizzy was southeast of me.
I found her soon after at the top of a black gum tree, just three quarters of a mile east north east of her previous roost location on October 11. I couldn’t actually see her, but her signal was localized in a raptor nest about 30 feet off the ground. Saw-whets have used similar abandoned nests for roost locations in the past, but according to Scott Weidensaul, nothing in the literature suggests this has been observed elsewhere. As I was collecting habitat data, six titmice flew in and were quite upset to find Dizzy, but did not stick around very long. This roost location is about 2.5 miles north east of the Small Valley banding station.
It will be interesting to see her roost movements in the next few days as temperatures drop, which may encourage Dizzy to continue her migration. On the other hand, Dizzy may choose to spend the entire winter in this area. We will continue to monitor her roosting activity as long as she stays in the area, and in the meantime, we will continue to patiently wait for more owls to arrive at King’s Gap. Again, last night the moon was too bright and temperatures were just too warm, and no owls were caught at any of the three sites.
Sunday, October 12, 2008
Picking up steam
The milder weather that has settled over the Northeast since mid-week hasn't been great for owl migration, but we're continuing to get one or two birds a night, mostly at our Hidden Valley station. (Small Valley was closed over the weekend while Girl Scouts were using the camp.)
Tonight all three sites will be running, as our third station, King's Gap in Cumberland County, starts up. Unfortunately, the mild southwesterly flow is going to continue for a couple more days, and the moon is rapidly waxing as well -- conditions that are less than ideal for fall migration, when we prefer to see a blustery cold front followed by nights of calm, cold and moonless skies.
But we're continuing to follow "Dizzy," the second-year female saw-whet we radio-tagged on Monday. Yesterday (Saturday, Oct. 11), I spent the day with research tech Anna Fasoli, looking for Dizzy in the Haldeman Tract of Weiser State Forest in northern Dauphin County.
When we met at Small Valley there was no whisper of a beep from the owl's radio transmitter, so we split up and each looped north along different routes into state forest, covering an area about six miles by three miles before reconnecting, driving slowly while listening through the white-noise static on our radio receivers and roof-mounted antennas for any hint of the signal.
Still nothing, so Anna suggested we drive out Wolf Pond Road, which dead-ends after about two miles at a steep escarpment where hang-gliders have a take-off ramp; it's a great overlook, she said, and might be a good spot to pick up a distant signal. But before we reached the hang-glider site, we both picked up Dizzy's signal, booming through the receivers -- she was holed up in a grove of white and pitch pines less than a hundred yards from the road.
Narrowing the search down to a yard-sized area was pretty easy; actually getting a look at Dizzy was not, and we spent nearly an hour shuffling back and forth, alternately waving our hand-held antennas and scanning the dense treetops with binoculars. The white pines were about 75 feet tall and very thick, and we could find no whitewash or pellets. And at that range, the signal was so loud it was hard to localize, even with the gain turned way down, so we tried an old telemetry trick -- jumping off frequency. Instead of setting the receiver to the correct frequency (say, .2850 MHz), we set it to .2950; this attenuates the signal considerably and allows one to take a more precise location. That got us down to one of two neighboring trees, so we jumped another hundred megahertz off the frequency, muting the signal so much that we could determine exactly which pine she was in.
And there she was -- by peering just so through a gap in the foliage, we could see her sitting about ten feet from the top of the tree, holding a deer mouse, on which she was actively feeding. Then it was merely a case of taking all the habitat data that we collect on both the roost site and a randomly selected site 20 meters away.
It's always a thrill to see one of our birds in the daytime, and Dizzy's been a good sport. Our hope is that when King's Gap opens, though, we'll be able to quickly tag an owl there, and shift the telemetry to our normal stomping grounds in Michaux State Forest, where access is a lot easier than we've experienced in the Weiser forest.
Here's a Google Earth image showing Dizzy's movements during the week; the Oct. 8 roost site is based on triangulation, and the colored block shows the rough area in which it may have been. (Lest anyone think we're jeopardizing her by giving out her location this way, consider how long it took us to find her with two radio receivers!)
Scott Weidensaul
Tonight all three sites will be running, as our third station, King's Gap in Cumberland County, starts up. Unfortunately, the mild southwesterly flow is going to continue for a couple more days, and the moon is rapidly waxing as well -- conditions that are less than ideal for fall migration, when we prefer to see a blustery cold front followed by nights of calm, cold and moonless skies.
But we're continuing to follow "Dizzy," the second-year female saw-whet we radio-tagged on Monday. Yesterday (Saturday, Oct. 11), I spent the day with research tech Anna Fasoli, looking for Dizzy in the Haldeman Tract of Weiser State Forest in northern Dauphin County.
When we met at Small Valley there was no whisper of a beep from the owl's radio transmitter, so we split up and each looped north along different routes into state forest, covering an area about six miles by three miles before reconnecting, driving slowly while listening through the white-noise static on our radio receivers and roof-mounted antennas for any hint of the signal.
Still nothing, so Anna suggested we drive out Wolf Pond Road, which dead-ends after about two miles at a steep escarpment where hang-gliders have a take-off ramp; it's a great overlook, she said, and might be a good spot to pick up a distant signal. But before we reached the hang-glider site, we both picked up Dizzy's signal, booming through the receivers -- she was holed up in a grove of white and pitch pines less than a hundred yards from the road.
Narrowing the search down to a yard-sized area was pretty easy; actually getting a look at Dizzy was not, and we spent nearly an hour shuffling back and forth, alternately waving our hand-held antennas and scanning the dense treetops with binoculars. The white pines were about 75 feet tall and very thick, and we could find no whitewash or pellets. And at that range, the signal was so loud it was hard to localize, even with the gain turned way down, so we tried an old telemetry trick -- jumping off frequency. Instead of setting the receiver to the correct frequency (say, .2850 MHz), we set it to .2950; this attenuates the signal considerably and allows one to take a more precise location. That got us down to one of two neighboring trees, so we jumped another hundred megahertz off the frequency, muting the signal so much that we could determine exactly which pine she was in.
And there she was -- by peering just so through a gap in the foliage, we could see her sitting about ten feet from the top of the tree, holding a deer mouse, on which she was actively feeding. Then it was merely a case of taking all the habitat data that we collect on both the roost site and a randomly selected site 20 meters away.
It's always a thrill to see one of our birds in the daytime, and Dizzy's been a good sport. Our hope is that when King's Gap opens, though, we'll be able to quickly tag an owl there, and shift the telemetry to our normal stomping grounds in Michaux State Forest, where access is a lot easier than we've experienced in the Weiser forest.
Here's a Google Earth image showing Dizzy's movements during the week; the Oct. 8 roost site is based on triangulation, and the colored block shows the rough area in which it may have been. (Lest anyone think we're jeopardizing her by giving out her location this way, consider how long it took us to find her with two radio receivers!)
Scott Weidensaul
Wednesday, October 8, 2008
Tracking Dizzy
With the high pressure cell settling in overhead, things slowed on the migration front Tuesday night, with no owls caught at either Small Valley or Hidden Valley, although the SV crew had a screech-owl close to the nets while they were closing up. (We often catch a few screechies each season that stumble into the nets, either by accident or because they were looking for a saw-whet for dinner.)
However, it was a very active day and night for the telemetry crew. Monday night after I left SV, Anna Fasoli and Drew Weber continued to track Dizzy, the owl we'd released earlier that evening, as she moved around Small Valley, the heavily wooded region where we band. They struggled with some areas where the topography produced odd signal bounce, but once it appeared Dizzy was settling in, they quit for the night around 1:30 a.m.
Late yesterday afternoon, Anna came back to try to find Dizzy's roost. She localized the signal fairly close to the cabin where we band, but neither she nor Drew, who joined her, could get a visual on the owl.
I'm not entirely surprised, because saw-whets can be maddeningly hard to spot - one reason they have long been assumed to be rare. Before leaf-fall, they generally roost high in the outer branches of hardwood trees, often an especially large tree that partially emerges from the surrounding canopy. What's more, they'll tuck themselves partway into a clump of leaves, so pesky flocks of chickadees and titmice don't spot them and raise a fuss. After the leaves drop, the saw-whets switch mostly to conifers, but finding a robin-sized owl in a pitch pine full of similarly sized cones is another challenge.
By about 7:45 p.m. EDT, Dizzy came off her roost. For the next two hours Anna and Drew were able to biangulate her position as she moved around, possibly hunting, but then the owl began to move more rapidly out of the area, and they soon lost her signal entirely. Despite a lot of hiking, followed by a lot of late-night driving on mountain roads through Weiser State Forest, they were unable to relocate her.
Anna will be going back to the banding site today in hopes that Dizzy returned to her previous roost -- or she may have decamped from the area entirely. This is the gamble we take every time we put a radio on a saw-whet; for every bird that sticks around for a couple of weeks, giving us lots of data, we get at least one that vamooses, taking our radio with it.
Scott Weidensaul
However, it was a very active day and night for the telemetry crew. Monday night after I left SV, Anna Fasoli and Drew Weber continued to track Dizzy, the owl we'd released earlier that evening, as she moved around Small Valley, the heavily wooded region where we band. They struggled with some areas where the topography produced odd signal bounce, but once it appeared Dizzy was settling in, they quit for the night around 1:30 a.m.
Late yesterday afternoon, Anna came back to try to find Dizzy's roost. She localized the signal fairly close to the cabin where we band, but neither she nor Drew, who joined her, could get a visual on the owl.
I'm not entirely surprised, because saw-whets can be maddeningly hard to spot - one reason they have long been assumed to be rare. Before leaf-fall, they generally roost high in the outer branches of hardwood trees, often an especially large tree that partially emerges from the surrounding canopy. What's more, they'll tuck themselves partway into a clump of leaves, so pesky flocks of chickadees and titmice don't spot them and raise a fuss. After the leaves drop, the saw-whets switch mostly to conifers, but finding a robin-sized owl in a pitch pine full of similarly sized cones is another challenge.
By about 7:45 p.m. EDT, Dizzy came off her roost. For the next two hours Anna and Drew were able to biangulate her position as she moved around, possibly hunting, but then the owl began to move more rapidly out of the area, and they soon lost her signal entirely. Despite a lot of hiking, followed by a lot of late-night driving on mountain roads through Weiser State Forest, they were unable to relocate her.
Anna will be going back to the banding site today in hopes that Dizzy returned to her previous roost -- or she may have decamped from the area entirely. This is the gamble we take every time we put a radio on a saw-whet; for every bird that sticks around for a couple of weeks, giving us lots of data, we get at least one that vamooses, taking our radio with it.
Scott Weidensaul
Tuesday, October 7, 2008
Off to the Races
After a slow start, things are finally hopping, and it's only going to get busier.
Sunday night we caught our first saw-whet of the season at Small Valley in Dauphin County, a second-year (SY) female which, in addition to a numbered leg band, also received the first radio transmitter of the season. The tiny, 2-gram device smaller than a pencil eraser is held in place in the middle of her back with a figure-eight harness of lightweight elastic beading cord.
The crew nicknamed the owl "Dizzy," because of the way she was spun up inside the mist net. After holding her overnight to make sure the harness wasn't interfering with her, we released her at Small Valley Monday night, and research technician Anna Fasoli, intern Drew Weber and I spent hours following her movements as she steadily shifted farther and farther east of the banding site.
This was mostly a shakedown for the intensive triangulation work we'll be doing this fall, using three tracking teams to simultaneously record bearings on the signal from the owl's transmitter, thus allowing us to plot its location through the night -- something that's rarely been attempted with saw-whets.
While we were tracking Dizzy, bander Guy Ubaghs and his SV crew caught two more saw-whets, including a "foreign recap," an owl banded elsewhere. When I find out where she was banded, I'll be sure to post it. Already this season, three of our owls from previous years have been reported, two in Ontario and one this weekend in western Massachusetts.
Over at our Hidden Valley site in Schuylkill County, bander Jim Logan Sr. and his crew had their first saw-whet of the season. Our third site, King's Gap, opens this weekend.
Driving to and from our sites at night is always a little dicey, given all the deer, but for the second time in little more than a week, I had to brake hard Monday evening on my way to Small Valley to avoid hitting a big black bear that loped across the road in front of me.
Scott Weidensaul
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