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Tracking project reveals Osprey migration feat

Osprey
BRINGING HOME CARRY-OUT: An adult Osprey named Lucky lands at his nest with a fish in August 2016 near St. John’s, Newfoundland. The nestling at left wears a tracking device with an antenna meant to record its migratory movements. Photo by Geoff Smith

I had been watching and photographing nesting Ospreys in my neighborhood for several years and had always enjoyed seeing their skillful flying and ability to catch fish. I thought I knew the birds pretty well, but in the summer of 2016, I took a series of photos that made me do a doubletake.

When I looked closely at the images on my computer screen, I noticed what appeared to be an antenna protruding from behind the head of one of the young birds. I had to know more, and my search for answers introduced me to a remarkable research project about the Osprey — one of the best-studied raptors in the world — and a dedicated scientist who has uncovered many of its secrets.

***

I live on the outskirts of St. John’s, a city on the island of Newfoundland, in the easternmost region of Canada. Years ago, the local power company installed a couple of nest platforms for Osprey in our area — a common practice in many places where the species breeds. The platforms are a win/win for the birds and for utility companies. The big raptors have learned to build their nests on the platforms and not on power substations and transmission-line equipment. The birds can raise their families without the threat of being electrocuted, and the companies avoid potential damage that could cost hundreds of thousands of dollars from nests shorting out the equipment.

Nearby is a large shallow lake surrounded mostly by coniferous forest, despite being within city limits. The lake is naturally well-stocked with trout. These factors combine to offer the perfect habitat for nesting Ospreys.

Like other raptor species that suffered catastrophic declines in population during the second half of the 20th century thanks to the effect of DDT poisoning in the food chain, the Osprey was once on the brink of extinction. When they consumed DDT occurring in the environment, Ospreys produced eggshells too thin to support the weight of incubating parent birds. Canada and the United States finally banned DDT in 1972.

Many decades later, the recovery of the Osprey has been remarkable. “Osprey populations here and elsewhere have recovered from their brush with extinction,” writes Pete Dunne in his superb book Birds of Prey: Hawks, Eagles, Falcons, and Vultures of North America. “The bird is once again a common breeder and migrant across much of North America, and I would not be surprised if the local breeding population was now as large as it was when Alexander Wilson visited these fecund shores two centuries ago.”

Osprey migration
TARGET IN SIGHT: Lucky stretches out his talons as he hunts for a fish at Virginia Lake, on the northeastern end of Newfoundland’s Avalon Peninsula. Overall, live fish account for more than 99 percent the prey taken by Osprey. Photo by Geoff Smith

Late in the summer of 2016, the nesting platform was home to an adult pair and a couple of fledglings, just as it had been for the previous year or two. The young birds were old enough to begin testing their flight abilities near the nest site. I had been photographing them for weeks when I first saw the antenna. My imagination drifted to thoughts of rogue states using Ospreys as spy drones or alien spacecraft cunningly disguised as a terrestrial raptor species. After coming to my senses, I contacted a local bird and wildlife expert at Memorial University of Newfoundland and asked him what may have sounded like a bizarre question: “Why are there antennae sticking out of the young Osprey in my neighborhood?”

He told me about OspreyTrax, a migration research project run by Rob Bierregaard, a world-renowned raptor scientist who has developed and attached GPS tracking devices on the backs of migrating Ospreys in several areas of the U.S. and Canada. His amazing, real-time GPS tracking maps can be viewed at www.ospreytrax.com.

Bierregaard first studied the species as a grad student in the early 1970s. He has researched the Ospreys of Martha’s Vineyard, Massachusetts, for over 40 years and has deployed satellite transmitters on nearly 100 juvenile and adult Ospreys from South Carolina to northern New Hampshire. He has authored or coauthored more than 60 scientific and popular articles on avian ecology and conservation and edited two major volumes on tropical forest fragmentation. He is a research associate at the Academy of Natural Sciences of Drexel University, serves on the board of directors of Audubon Pennsylvania, and is the president-elect of the Raptor Research Foundation. And in 2018, he published Belle’s Journey: An Osprey Takes Flight, a book for middle-schoolers.

On Newfoundland, Bierregaard was particularly interested in the first-year southerly migrations of Ospreys fledged from nest sites on the island because, after years spent tracking young Ospreys from Martha’s Vineyard, he had an interesting theory about the young Newfoundland birds. The antenna I had seen in my photos was attached to one of Bierregaard’s tracking devices. It was on the back of one of the young Ospreys soon to fly all the way from Newfoundland toward the Gulf of Mexico and perhaps beyond.

“In the 1970s, scientists began using radios communicating via satellites to track animals in remote areas,” Bierregaard explains. “The first radios were huge, and only very large animals could carry them. By the 1990s, transmitters had become small enough to put on birds. 1995 saw the first transmitters deployed on Ospreys.”

Since 1995, more than 500 Ospreys have received transmitters — 200-plus in Europe and about 320 in the U.S. Bierregaard says that about 300 were adults and 227 were juveniles. “Before 2000, the vast majority of Ospreys tagged were adults. Since then, more juveniles have been tagged,” he says. “In the early years, we knew nothing of the details of adult mortality, so that’s where the big questions were. Additionally, adults have a much higher survival rate than juveniles, so it made little sense to risk $3,000 to $4,000 transmitters on juveniles.”

Data from tracking studies revealed that adult females head south up to a month before males, that Ospreys adhere to certain migration flyways but not specific routes, and that breeding pairs don’t migrate or overwinter together. And adults do not migrate with their offspring.

The wintering range for this widespread bird of prey extends from southern Texas and Florida through the Caribbean and Central America south to central Chile and Argentina. More than 75 percent of the birds that breed in eastern North America winter in South America.

“After 2000, with the big questions about Osprey migration effectively answered, interest in tagging juveniles increased,” Bierregaard says. “Many of the young tagged since 2000 have been young that were translocated and released in reintroduction programs. Most (61) of the rest of the young tagged have been part of the OspreyTrax project.

“The next big step forward was adding solar power, which enabled us to follow birds through several migration cycles. Then GPS receivers were added to the transmitters, so we can now get accuracy down to 10 to 15 yards. Not only do we get remarkably accurate locations (we can often tell what tree a bird is perched in), but we also get speed, direction, and altitude for each fix.”

SHAKE IT OFF: While carrying his next meal, Lucky shakes water off his head. When Ospreys catch a fish, they’re partially submerged, so getting airborne requires powerful wing strokes while grasping prey that can weigh 10-30 percent of their body mass. Photo by Geoff Smith

***

Bierregaard banded some of the parent Ospreys that nest in my area of Newfoundland. They received leg bands while he was in the process of attaching GPS trackers on the young birds. Some of the adult birds were fitted with GPS trackers, as well. One of these adults turned out to be a male bird I had been watching fish for trout for several years at nearby Virginia Lake.

The research team named the bird Lucky and, of course, assigned him a band number. Lucky came by his name while Bierregaard’s team was netting and banding him. He was also slated to have a GPS tracker attached, but the team realized it had already used the last tracker it had available for Newfoundland Ospreys. So, it named him Lucky because he got a break and was released after only being weighed and banded.

He received one of Bierregaard’s unique-looking, unusually wide alloy bands. A couple of years later, it was established through a process of elimination that Lucky was the last remaining male of the birds banded for the OspreyTrax research on Newfoundland. Each year, I would see him return to take a mate and fish at Virginia Lake. He was defying the odds of many of the Ospreys that make the long and perilous migrations to and from our island in the North Atlantic each year.

I now had both his familiar underwing plumage pattern and the unique wide alloy band on his left leg to easily identify him by. Each year, I marveled at his return and happily photographed him at the nest site and while he was diving for fish.

In early 2018, a documentary film producer based in Bristol, in the United Kingdom, contacted me after receiving a recommendation from a fellow Newfoundlander. They were coming to shoot footage on the island and, after seeing my Osprey photos on social media, wanted to hire me as a Bald Eagle and Osprey guide for their camera crew.

Camera operator Tom Rowland and I spent many hours capturing footage of Lucky fishing for trout at Virginia Lake. Seeing this individual Osprey, which I had come to know so well, presented in super slow-motion flight through the technological marvel of high-speed camera footage in the finished documentary was yet another memorable milestone in my ongoing connection with Lucky the Osprey. The doc aired in the U.K. in the fall of 2018, and it’s still being shown in reruns there to this day. The series, “Canada: A Year in the Wild” (Tigress Productions/Channel 5), was a great success in the U.K. (In the U.S. and Canada, it’s available to watch on Amazon Prime; Lucky is featured in the third episode, “Spring.”)

THE EXPERT: Rob Bierregaard releases an Osprey in 2014. Since 1995, the world-renowned raptor scientist has deployed satellite transmitters on nearly 100 juvenile and adult Ospreys, and he has extensively studied the Ospreys of Martha’s Vineyard. Photo by Craig Gibson

One of Lucky’s offspring, a young female that was banded and fitted with a GPS tracker on Lucky’s nest site in 2016, was the individual bird that proved one of Bierregaard’s most interesting theories correct. She was named Virginia (after the nearby lake) and was one of the two young Ospreys I had first seen with antennae sticking out from behind their heads on the nest site in my neighborhood.

After Bierregaard saw young Ospreys from Martha’s Vineyard show up in Bermuda, he suspected that the birds fledged from nests on Newfoundland’s Avalon Peninsula, which is the most easterly point of land in North America, might do the same. If they did, this would mark an over-open-ocean distance record surpassed only by one other bird of prey in the world (the Amur Falcon, which crosses the Arabian Sea from Asia to winter in southern Africa).

“Virginia went south to the tip of the Avalon Peninsula and then, after a bit of fishing at Peters Pond just to top off the tanks, headed south over the Atlantic,” Bierregaard says. “This is in stark contrast to what our two Newfoundland Osprey adults, Daphne and Shana, did. Having done this migration thing before, they knew that the safe way to their wintering waters is to go west first and then down the east coast of the U.S. They would have ‘discovered’ that on their first trip north.”

Virginia didn’t follow the coast but flew due south over the ocean, exactly as Bierregaard predicted. She left Newfoundland at about 7 a.m. on October 4, and for nine hours, she flew straight south-southeast and then made a turn to the southwest. She was on course toward either Bermuda or the east coast, but after about 72 hours flying over the Atlantic, she sadly ran into Hurricane Matthew, a Category 5 storm that barreled up the coast in early October. She died along the coast of South Carolina.

Despite the unfortunate outcome, Bierregaard said the study proved successful.

“This is what the whole Project Newfoundland expedition was all about — documenting naive Ospreys making their first trip south without a genetic map for the route to the wintering grounds,” he says.

Virginia’s GPS track final numbers were remarkable: 82.5 hours of flight, 2,227 miles (3,584 km), at an average speed of 27 mph (43 kph).

“The whole trip was fascinating and confirmed what we had predicted for juveniles from Newfoundland — that they would head south over the Atlantic,” Bierregaard adds. “I was surprised when she turned west but then discovered that she was flying around an oncoming weather front. After she got past the storm, she turned south again and was headed for the Bahamas until she flew into the edge of Hurricane Matthew. The winds of the storm blew her northwest to the shore of South Carolina, where the storm then rolled over her.”

Bierregaard made two trips to Newfoundland to tag Osprey — the last of his 17-year satellite tagging program. “It couldn’t have ended any better — except if more of the young had survived,” he says. “Science at its best. I had observed over half the young from Martha’s Vineyard migrating over the Atlantic and predicted that the young from Newfoundland would do the same. So, I mounted one last expedition to test my hypothesis and, sure enough, the Newfoundland birds — at least Virginia — proved me right.”

SURVEYING THEIR WORLD: Two of the three young that Lucky and his mate fledged in August 2020 perch atop a tree in the week that they left the nest. Photo by Geoff Smith

***

The year after my experience helping make Lucky a TV star, I was very pleased to see he had returned to my neighborhood to mate and fish at Virginia Lake, surviving yet another perilous migration. To my absolute pleasure and joy, he returned again in the spring of 2020. His resilience and tenacity are certainly something to be admired.

Local birders and Osprey enthusiasts who recognize his underwing patterns have estimated his age to be at least 12 years, based on sightings that go back that far. Banding records show the oldest known Osprey in North America lived to be 25 years, 2 months, and a female in Scotland lived to be at least 27. A few others have lived into their early 20s, so Lucky might be considered to be in the prime of life. To me, an Osprey with so many cycles of long-distance migrations already completed is mighty impressive. 

It will be a strange feeling if in 2021 or a later year I wait for Lucky to show up in early May and he does not return. How many more years does this tough old bird have in him? I have lost count of how many young he has sired while I’ve been observing him. Perhaps when Lucky does not return, it will be one of his offspring I will watch and photograph diving for trout at Virginia Lake.

A thriving bird of prey

From the 1950s to the early 1970s, pesticides including DDT caused Osprey populations to plummet. By the time DDT was banned, only 10 percent of the Atlantic Coast population in North America remained, and the bird was feared to be headed toward extirpation in many areas.

Now, it is a symbol of conservation success. The global population may be as high as half a million mature individuals. A 2001 estimate of breeding numbers in the lower 48 states found 16,000 to 19,000 pairs, which was up 25 percent from 1994. Since then, numbers have continued to grow around the country to the point where most states no longer monitor the species, making a reliable continental population estimate virtually impossible.

“Although small pockets of contamination remain, the historic range has greatly expanded and many populations in Canada and the United States now exceed historical numbers, owing to a cleaner environment, increasingly available artificial nest sites, and this bird’s ability to tolerate human activity near its nests,” says the Birds of the World species account coauthored by Rob Bierregaard. “Phoenix-like, the Osprey has arisen from the ashes of its own demise, a survivor, even a backyard bird in some areas today. Indeed, there is little wonder the species has become such a powerful totem for conservation.”

This article was first published in the May/June 2021 issue of BirdWatching magazine

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Geoff Smith

Geoff Smith is a bird and wildlife photographer from St. John’s, in the Canadian province of Newfoundland and Labrador. View his photos at https://500px.com/wayouteast.

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