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Barred Owl Research - Overview

Introduction

According to the text books, Barred Owls are supposed to need large stands of old-growth forest to survive. Yet the species is abundant throughout the older suburban neighborhoods of many cities in the southeast. Intrigued by this apparent contradiction, we initiated a study of Barred Owls in the Charlotte region in the central Piedmont of North Carolina in 2001. One of our initial question, simply put, was whether the books were wrong or have the local Barred Owls simply neglected to read the books?

      Over the subsequent 8 years three graduate students, a small flock of undergrads, and I have studied Barred Owls in both suburban and rural habitats around Charlotte. Besides figuring out what Barred Owls are doing in this unusual habitat, we are comparing the natural history of the two populations. Are the city birds reproducing as well as their country cousins? Are territory sizes the same? How exactly do the two habitats compare structurally? Do the city and country birds rely on the same prey species? How far do the young travel when they leave their natal territories?

Censuses

In 1971,

Radio Telemetry

In 2000

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Mid June 2014 Update

(Scroll up for other updates and links to more on the OspreyTrax site.)

Foiled in New Hampshire

After my successful trip to the upper Chesapeake Bay, in late May I headed north for another round of trapping. And I do mean north. On the 29th of May, along with Iain MacLeod, my partner in the study of the inland-nesting Ospreys of New Hampshire, I headed to the upper reaches of the Connecticut River, just 20 miles south of the Canadian border. We planned to trap the male that replaced Mackenzie, the unfortunate adult male we tagged last year. Mackenzie was killed by a Goshawk or a Great-horned Owl before he could start his migration.
     The image above, taken from our target nest shows the Connecticut River, with New Hampshire on the right and Vermont on the left. We did trap the female and confirmed that she's the same bird we trapped at this nest in 2012 in an unsuccessful attempt to tag her mate.
    In 2013 we were able to trap the male (Mackenzie) at this nest, but this year we were once again frustrated here as we tried to tag Mackenzie's replacement. We caught the female in just a few minutes, replaced her three eggs with wooden dummies so there wouldn't be any problems with the eggs chilling, and waited for the male to move in and do his paternal thing.
     Nothing doing. He was just not interested. We do occasionally encounter males with very little inclination to engage in the care of eggs. This might be a young male in his first breeding attempt who just hasn't figured it all out, yet. So, after it became clear that we were not going to catch our target bird, we removed the trap from the nest, swapped the real eggs for the dummies, moved everything away from the nest, and released the female. She was back on the nest in very short order.

At the other end of the Connecticut River

240 miles south, the Connecticut River looks a little different. This aerial view (not from a nest!) shows the wide expanse at the river's mouth where it opens to Long Island Sound.
This is Osprey Mecca. In the pre-DDT era (before WWII) the 200 pairs nesting in this area formed one of the three major colonies in southern New England and Long Island. Many pairs nested on the marshy islands, like the one on the left in this aerial, either right on the ground or on the roots of trees that floated down the river and landed on the islands.
     In the 1950s and 60s, as DDT worked its way up aquatic food chains, Osprey populations crashed. In this colony, the alarming decline occurred under the watchful eyes of Roger Tory Peterson, who sounded the alarm. 
     At first we didn't know why reproduction was so poor--was it something to do with the eggs, or could the parents not raise young that hatched? Peterson, along with Gerry Mersereau (more on Gerry below) and Peter Ames, thought the problem might have been predation on ground-nesting birds or flooding at spring tides, so they erected nesting platforms. The Ospreys quickly took to the platforms, but this didn't help them fledge more young.
     Paul Spitzer then definitively answered the question by reciprocally swapping Maryland eggs (some Maryland Ospreys were doing much better than Connecticut birds) with Connecticut eggs. His work showed that the problem was in the eggs, not the parents' ability to feed young. Maryland adults couldn't hatch Connecticut eggs, while Connecticut adults did fine with Maryland eggs. That was part of the process that led to fingering DDT as the main culprit in the collapse of the population.
    Four decades later, I set up my spotting scope on Griswold Point, right at the mouth of the river and scanned the Point, Great Island, and adjacent Smith Neck. When I had finished the scan I had counted a remarkable 56 Ospreys and about 30 nests. And those were just the birds that were incubating eggs or perched near their nests. The whole time I was counting, Ospreys were coming into the colony with menhaden--probably their favorite fish--or heading out to hunt.
    As I watched all those Ospreys, I thought about how depressing it must have been to study this colony in the early 70s, when over a three-year period about 25 pairs were unable to fledge a single young. 
     How different it is now! The population is growing, all the platforms seem to be occupied, birds without a nest platform are nesting on the ground, and some are "going retro"--nesting in trees!

Connecticut River Tagging

I arrived in Old Lyme, at the mouth of the Connecticut River on May 31st to work with Paul Spitzer, who is back in his natal territory to survey the Connecticut River colony 40 years after his seminal studies of the Long Island Sound Ospreys in the dark days of the DDT decline. On June 1st we set out to put cell-tower transmitters on two adult males. All went perfectly. At our first nest, on Griswold Point, we quickly (maybe 4 minutes after setting the trap) caught the female, and then got the male just a few minutes later. The male was already banded. We named him "Gerry," in honor of Gerry Mersereau (mentioned above) who banded Ospreys from the 1960s through 2005 when he passed away. It came as no surprise when we found out that our "Gerry" had indeed been banded by Gerry Mersereau on 23 June 1998. (See Gerry's maps.)

After lunch, we set our trap at a nest on Smith Neck. Once again, we quickly caught both the female and male. Both were banded! The male's band looked old, and indeed it was. He was banded by Mersereau in June of 1997, so he is 17 years old. The female is a relative youngster. She was banded 8 years ago by personnel of the CT Dept. of Environmental Protection. We named the male here "Roger Tory" for obvious reasons. (Follow Roger's maps.)

 On June 2nd we were out trapping again, this time at a nest less than 150 meters from Roger Tory's nest. Once again, trapping went perfectly. The whole process, from setting the trap to tagging and releasing the male, took only 51 minutes. We named this male "Uncas." Uncas was a sachem (chief) of the Mohegan tribe in lower Connecticut. (See Uncas' maps.)

Chesapeake Bay Update

     

Not much news from Chesapeake Bay. Down on Tangiers Island, based on the results from their transmitters, Nick did not nest, and Quin seems to be feeding young. I'm still waiting for confirmation from the ground.
     Further up the Bay near Annapolis, all seems well with Woody, who nests near the Annapolis side of the Bay Bridge. Across the bridge, on Kent Island my eyes on the ground report that Chester is now the proud father of three chicks. (Follow Chester's maps.)
     Our most interesting bird on the Bay is the newly tagged Crabby. Crabby was "by-catch," if you will, of our trapping attempt at a nest on Cox Neck (near Chester's nest). We couldn't catch our target bird--the male at the nest--but did catch a hanger-on female and decided to tag her. She's obviously a relatively young bird that does not have a nest yet.
     Not having a nest, Crabby is free to wander around. Right after we caught her, she started commuting between Cox Neck and Tuckahoe State Park where she fished Tuckahoe Creek. She made 5 trips from Kent Island, where we caught her, to Tuckahoe Creek. Jim Uphoff, a fisheries biologist with Maryland's Dept. of Natural Resources, reports that Alewife, Blueback Herring, Hickory Shad, Gizzard Shad, as well as Yellow and White Perch run up Tuckahoe Creek. All of those are favorite Osprey chow. (Follow Crabby's maps.)
     In DC, our two satellite tagged birds, Ron and Rodney, seem to be fine, although neither nested this year.

New England Update

Our first addition to the New England flock, Charlie, was feeding three young at his nest on Fishers Island. His movements have been quite surprising (follow his maps).

The two surviving New England cell-tower birds from last year are doing well, although Edwin (Fishers Island) did not nest this year. He has been wandering all over eastern Connecticut and even down to Gardiners Island.

DJ, a male from Martha's Vineyard, is feeding 2 young. I'm pretty sure this is the first time he has gotten this far in the nesting process. In previous years he (presumably) and his female tried nesting on top of a dune, with predictable results, given the number of skunks and raccoons wandering around the island.

Snowy and Belle, our Martha's Vineyard sub-adults tagged with satelite transmitters as juveniles in 2011 and 2010, respectively, continue to commute between Cape Cod and the Vineyard. Both are spending more time on the Cape.

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Late Summer 2014 Update

(Scroll down for earlier updates or scroll up for an overview of the research and links to more on the OspreyTrax site.)

Follow our birds on your smart phone!

Our colleagues at Movebank have developed a mobile App for iPhones and Android devices. It's called "Animal Tracker" and is free. Launch the App and click on the North American points--they're all our Ospreys. Click on one of the icons and you'll see a screen like the one below. If you click on the 2-week or 1-year movement data, you'll see an animation of the bird's movement in that time period. You can also add observations of tagged animals if you track one down using the App. Way cool!

Five new young tagged

On August 3rd I traveled up to eastern Long Island to begin the summer trapping season.
     On the 4th we trapped a young male on the north shore of Peconic Bay in Southold, NY. His nest, out on Long Island's North Fork, is the same nest where we tagged Pearl last summer. 
     When we set up to trap, there was nothing going on at the nest. Both young were off exploring somewhere. One of the neighboring youngsters made a pass over the nest, where we had our trap baited with a nice fresh porgy. The intruder was a bit skittish about landing the nest with the trap on it and flew back to its nest down the beach.
     "Clyde" came in after about 40 minutes and landed right on the trap and was caught quickly. We took him down for processing, removed the trap, and left the fish in the nest. As we were outfitting him with his new transmitter, the young neighbor slipped in and snatched the porgy! Clyde weighed 1.26 kg, just under 3 lbs., which is pretty typical for a young male.
     Clyde's transmitter has been lucky for us, but not for the birds who have worn it. The first bird to carry it was Tucker. Tucker was the adult male at our other "old faithful" nest on the North Fork golf course. He was hit by a bus a month or so after we tagged him. 
     Then we put the transmitter on Cutch, a young, non-breeding male caught while trying to pilfer our bait fish at the North Fork GC nest (I detect a theme here). Cutch made it to Colombia, only to impale himself on a submerged snag while trying to catch a fish.
     Bad luck for the birds, but good luck for us--the transmitter survived the crash with a bus, and it was pretty amazing to get the transmitter back from Colombia.
     Let's hope the luck changes for the birds. Third time's the charm? And we hope our luck will stay good if Clyde lives a long life with the transmitter and we don't lay our hands on it for a long time.

     

After a foiled attempt to retrap DJ on Martha's Vineyard, I headed up to northeastern Massachusetts with two transmitters to deploy on recently fledged young. (There is no reason for DJ to carry the transmitter south again. We already know he's going to the same place and will probably take a slightly different route.) One of the transmitters was recovered, rather remarkably, from Whit--a youngster tagged last year in this area. Whit was killed crossing a highway down in northern Venezuela. Thanks to the internet, we had the transmitter back in the States about 3 days after we noticed that the transmitter wasn't moving!
     In this area, I work with Dave Rimmer of the Essex County Greenbelt Association, the organization that sponsored two transmitters this year. Greenbelt, Essex County's Land Trust, has an Osprey nest-cam on the marsh right in front of their offices. We set our trap at the nest in the marshes of the Allyn Cox Reservation by 6:10 AM. We didn't have to wait long before we caught the adult female. While we were banding her, her young came in and landed on the nest and was quickly trapped. "Flow" is a really handsome youngster--another bird with a distinctively dark head. He weighed in at a pretty typical 1.28 kg--2.8 pounds.
     As an only child, he's getting lots of food. Every time I log onto the Greenbelt Osprey cam, he's chowing down on a big ol' fish.      

We then headed up to the mouth of the Merrimack River in Salisbury State Beach Reservation. We set our trap on a nest atop an abandoned, rickety old duck blind along Black Rock Creek, which feeds into the Merrimack not far from the Massachusetts/New Hampshire border. There were 2 young perched on the nest as we boated up the creek.
     It was a long day on the marsh, including an emergency run to get ice cream at one point. After 3 hours with little or no sign of the young, we caught an adult female--probably the female from this nest. She was a monster--weighing 2.2 kg, almost 5 pounds!--the biggest Osprey I've ever held.
     After a couple more hours of no action on the nest, we moved the trap to a neighboring nest pole where we'd seen birds perched the whole day we were out there.
     About an hour later, with the tide dropping fast and thus little time left, we caught both young at the new nest. Thus we had a choice of which bird to tag. I noticed a slight cut on the female's wing (it was an old injury--not one suffered during trapping), and so we chose to tag her brother. "Blackie" is quite dark, which, along with the location of his nest on Black Rock Creek, gave us the idea for his name.
     He is a robust young male, weighing in at 1.38 kg, which translates to just over 3 pounds. Since he was trapped, he's rarely left his nest, which fits the behavior we witnessed out on his marsh.

     Then it was off to New Hampshire, where I teamed up with my colleague Iain MacLeod, Director of the Squam Lakes Natural Science Center, and we visited our two favorite nests in the Lakes District.
     We began the day at the JJill distribution facility in Tilton at the nest where we tagged Donovan in 2013. In 2012 we tagged 2 fledglings, Jill and Chip, at this nest. Chip, you may remember, is the bird who rode ships east across the Atlantic until he was lost at sea.
     We set the trap at 8:30 with both of the 2 young from the nest and their parents circling around and complaining about our invasion of their space.
     It was a pretty long wait. At 11:30, a male landed on the perch above the nest and stared down at the herring we had left under the trap. About 10 minutes later, "Tilton" hopped down onto the trap and was caught.

We were hoping to trap Donovan and get his transmitter back, but he wasn't having anything to do with the nest after he saw us around it again. You know the old saying, "Fool me once, shame on you, fool me twice, shame on me," Donovan lives by that and will keep the transmitter for at least another year.
     Tilton has an interesting plumage. His head is rather dark and he has quite a dark chest band for a male.
     He's a bit of a pipsqueak. He weighs only 1.06 kg (about 2.3 lbs), but didn't feel thin, so I was OK with deploying the transmitter on him. He's a healthy pipsqueak. 

      After lunch, we returned to our old faithful nest at the Bridgewater Power plant on the banks of the Pemigewasset River. (Oh, how I love the place names in New England!) As usual, when we arrived, there were plenty of Ospreys flying around the nest. We set our trap at 1:30 and 6 minutes later (a record) had a bird on the trap. 

"Bridget" is the 50th juvenile Osprey I have tagged. She's most likely a small female. She weighed 1.5 kg (3.3 lbs), which would be a big male or small female. Her wing length suggests she's a female, so that's our working hypothesis.
     Bridget is the daughter of Art, who wore a radio from 2012-2013. She's also the sister of Artoo, who now is wearing the radio Art carried to Brazil and back. Artoo is down on the Amazon deep in Brazil. He'll come back in about 8 or 9 months.
     She has 2 siblings. This is the second year in a row her very productive parents have fledged 3 young. In 2012 the nest blew off its pole in a violent storm. It was securely replaced, but the young couldn't be saved.

Update on tagged adults

Up in New Hampshire, Donovan is feeding two fledglings, one of which (Tilton) is now wearing a new satellite transmitter. Donovan has expanded his range a bit to the west, perhaps because the nests of his two neighbors over that way failed this year.

In the Cape Cod/Martha's Vineyard area, Belle (2010 fledgling) is now 4 years old but still doesn't have a soul--I mean nest mate. Just as she did last year, she spent the early part of the summer commuting between the Falmouth area (western Cape Cod) and the Vineyard. Now she's crossing Buzzards Bay, moving back and forth between Falmouth and Marion.

Snowy (tagged in 2011 as a fledgling on the Vineyard), spent the spring and early summer commuting between Long Pond in Falmouth and the Katama Bay area, where he was born. In early July he took a spin up towards Boston, returned to the Cape and then headed west to southwestern Connecticut--just like he did last year. This year he made a quick trip back to the Cape/Vineyard and then returned to Connecticut, where he was fishing the Stamford Reservoir. He's now down in western Long Island.

DJ, an adult male tagged last year, is turning out to be a dead-beat dad. He and his mate have one young in the nest, but it is emaciated and probably will not survive. This is the first year this young pair has had a young this old. When we tried to catch DJ, he was away from the nest for almost 7 hours and the female was doing all the hunting for the family. Maybe they'll sort it out next year.

Down in the Long Island Sound area, all sorts of interesting things are going on. 

Edwin, tagged at his nest on Fishers Island last year, did not nest this year. He's made a couple of cameo appearances on Fishers Island, but has not spent any time there at all. While he's not been on Fishers, he's been pretty much all over the rest of the map around Long Island Sound. He has been as far east as Rhode Island and settled down for a bit a couple of times at the famous Gardiners Island Osprey Colony. He's recently been working the Connecticut River and has been fishing close to at least one of our birds tagged this spring at the mouth of the river.

Meanwhile on Fishers Island, Charlie, tagged this spring, and his mate raised two young at their nest at the Fishers Island recycling center. Charlie spent much of the early breeding season commuting 7-10 miles each way from Fishers to New London, where he was fishing the Thames and Niantic Rivers. For the past few weeks, he has been doing all his fishing around the western end of Fishers Island. 

North-Fork Bob has still not found true love, Osprey style. He's been across the Sound to Connecticut a couple of times, but has mostly been out around his usual haunts in eastern Long Island, mostly hunting out in Peconic Bay. Recently, I've noticed that he has been visiting an big field close to his normal resting area along Deep Hole Creek. He's there most afternoons--sometimes on a pole line in the field, but more often just out somewhere in the middle of the field. This made no sense until I visited the field in early August. It turns out that there is a big irrigation thingamajiggy that moves around the field, which is clearly where he has been perching. This makes no sense, unless he's checking it out as a nest support structure for next year. Could we have the first Ospreys with a mobile home?

Across the Sound at the mouth of the Connecticut River, Gerry and Uncas raised young and did what we expected, which is to say they spent most of their time fishing for menhaden around the mouth of the river. Roger Tory, whose nest failed, surprised us by commuting pretty much daily 20 miles each way all the way up to the Salmon River, which is richly stocked with trout.

Down in the Mid-Atlantic region, Woody and his mate may or may not have raised young. We don't have reliable eyes on the ground there, so we're not sure. We do have a photo of Woody on his nest with another bird, but the lighting is bad, so it could be the female or a young. It's pretty unusual for both the male and female to be on the nest together this late in the season, so I suspect they raised at least one young.

Across the Bay on Kent Island, Chester and his mate fledged two young. He spent most of his time fishing in Eastern Bay. Crabby, our non-breeding female, after her junket east of the Bay, settled down in the Kent Island area. She liked one spot in particular south of the nest where she was trying to insinuate herself. We'll be watching that spot when she comes back next spring. Unmated females in the spring are looking for young males without a mate, or older males whose mates didn't return from their wintering grounds. Paul Spitzer's research in the Chesapeake showed that young birds can take more than 5 years to establish themselves in a breeding pair in an area with a dense Osprey population.

Further down the Bay on Tangiers Island, Nick did not breed this year. Very frustratingly we don't have any reports of what happened with Quin's nest, but at least we know that he was paired up and nested. Both Quin and Nick fished around Tangiers pretty much in the same areas they did last year. 

Moving inland up the Potomac River to Washington, DC, Ron and Rodney both got back so late that their mates from last year had already paired up with new males. Ron certainly didn't breed, but Rodney may have established a late pair on one of the other pilings on the South Capital St Bridge over the Anacostia River where he and Rodney were trapped on their nests in 2013.

Meanwhile, down along the banks of the mighty Amazon, Artoo is doing fine. He spends most of his time at a small lake just south of the river, but he's now been travelling up to the river to do some fishing and exploring. He'll head north next spring sometime.

Fall Migration preview

Shorebirds have been moving south from their arctic breeding grounds for almost a month now, and warblers are beginning to show up, so our Ospreys will be moving soon. In fact, the hawk watch site at Corpus Christie, TX, has already reported the first Ospreys of the season. These will almost certainly be females--probably from failed nests--because adult females leave before males. Most females head south in mid to late August. Most males and juveniles start their migrations in the first two weeks of September.

This year I tagged 11 birds--6 adults and 5 juveniles--and we had a good return of birds previously tagged this spring, so we'll be following 22 birds as they move south starting any day now.

Here are the dates that our 11 "veterans" started south last year:

Snowy 8/14
Edwin 8/16
Woody 9/3 
Rodney 9/3
Nick 9/13
Ron 9/14
Donovan 9/17
DJ 9/17
Belle 9/17
Quin 9/17
North-Fork Bob 9/24

It seems the start of fall migration is not as similar from one year to the next for an individual bird as is the start of spring migration. Birds in the fall are in no real hurry to get south, so they are more likely to wait for just the right weather--a nice strong wind out of the north--in the fall than in the spring. In the spring, they're in a rush to get home to make sure no usurper tries to take over their territory, and I don't think they get big weather systems moving in with strong winds out of the south to urge them on. So I think the northbound trip starts with some combination of hormone levels rising and an internal clock telling them it time to get back to the breeding grounds.

Keep checking the interactive maps--or check your new Animal Tracker app!--to see when our flock starts moving south. And let's hope we have as benign a hurricane season as we did last year, when we didn't lose a single bird crossing the Caribbean.

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