In the Field

The Mystery of Pennsylvania's Lesser Black-backed Gulls

By David Barber, Research Biologist
Hawk Mountain Sanctuary

We stood around the back of the pick-up truck tearing up day old bread, cookies, and muffins into bite-sized pieces.  When we thought we had enough, Pennsylvania Game Commission biologist, Patti Barber, grabbed a bag and walked to the middle of the vacant parking lot and started tossing pieces into the air.  Within seconds ring-billed gulls came flying in to take advantage of the free meal.  But these gulls weren't the reason we were all gathered on this cold March day at Nockamixon State Park.  Patti was after lesser black-backed gulls.

Adult lesser black-backed gull with satellite transmitter. Photo by Pat Rago.

Adult lesser black-backed gull with satellite transmitter. Photo by Pat Rago.

Lesser black-backed gulls have captured the attention of Pennsylvania's birdwatchers ever since they first started showing up in winter in southeastern Pennsylvania in the 1960’s.  You see, lesser black-blacked gulls do not nest in the United States and these birds typically appeared in November and disappeared in March.  Where were these birds coming from and where were they going?  Armed with 10 satellite transmitters, Patti along with biologists from the Game Commission, Massachusetts Department of Conservation and Recreation, and Hawk Mountain Sanctuary hoped to find out. 

While the ring-billed gulls were not shy about coming into the buffet, the lesser black-backs were more aloof, standing off to the side of the food scrum, just outside the range of the rocket net.   They had to come into the center of the feeding frenzy in order to fire off the rocket net.  By moving around with the food Patti was able to manipulate the flock's movements.

Hawk Mountain Research Biologist David Barber and PA Game Commission Biologist Patti Barber check the fit of a satellite transmitter before releasing a lesser black-backed gull. Photo by Pat Rago.

Hawk Mountain Research Biologist David Barber and PA Game Commission Biologist Patti Barber check the fit of a satellite transmitter before releasing a lesser black-backed gull. Photo by Pat Rago.

By late afternoon, the flock finally moved so the lesser black-backed gulls were in the target zone.  With a boom the net arced out over the gull flock ensnaring nearly 80 gulls, a mix of ring-billed, herring, and lesser black-backed gulls. Everyone mobilized, releasing the ring-billed and herring gulls and saving the prize, 20 lesser black-backed gulls.  By the time all of the gulls were released, the sun was setting and the cold was seeping into our fingers.  Not willing to simply release our captives, we needed to need to find a warm, bright spot where we could band the birds and attach the satellite transmitters. 

We drove back to our house, turning the garage into a make shift banding station.  The immature gulls were measured and banded, while the adults received both a band and a satellite transmitter.  We finally finished processing the last bird at 2 am and caught a little sleep before driving back to Lake Nockamixon to release the birds at sunrise.

According to Patti, the transmitters are providing a wealth of information, the birds don't just spend the winter at Lake Nockamixon, but often commute to different water bodies in southeastern Pennsylvania and central New Jersey, including Green Lane and Peace Valley reservoirs in PA and Spruce Run and Round Valley reservoirs in NJ.  Some even spent time on the NJ shore before commuting back to Lake Nockamixon. 

Movements of  lesser black-backed gulls through June 2018. Map by PA Game Commission.

Movements of  lesser black-backed gulls through June 2018. Map by PA Game Commission.

And where do these birds go in the spring? Of the 9 birds that were tagged with transmitters in 2018, one transmitter stopped working before the spring migration, but five of the birds spent the summer in Greenland and three spent the summer in Quebec, Labrador and Newfoundland, Canada. 

As of early February, six of the gulls returned to southeastern PA, one was wintering in Virginia, but is heading north to PA and one transmitter failed on the breeding grounds.  An additional satellite transmitter was deployed on an adult bird last week and is hanging  out at the New Jersey reservoirs.

Thanks to the Pennsylvania Game Commission with help from Hawk Mountain Sanctuary, the Massachusetts Department of Conservation and Recreation and volunteers, we are well on our way to solving the mystery of Pennsylvania lesser black-backed gulls. 

Visit the Game Commission's Lesser Black-backed Gull project page for updates as they become available.

Land of the Sky Clowns

By Zoey Greenberg, Science Outreach Leadership Trainee
Hawk Mountain Sanctuary

King Vulture

King Vulture

King vultures are ridiculously handsome scavengers. When one of these color collages fixes you with a bright yellow gaze it’s akin to locking eyes with a sky clown, though somehow the moment feels un-funny. True to their name, they carry an air of royalty that is impossible to ignore and as a species, they are a breathtaking compliment to the diversity of the natural world.

I saw my first king vulture this month in Costa Rica, as I joined senior research biologist JF Therrien and former trainee from 1999, Pablo Porras, to assist in Hawk Mountain’s vulture surveys as part of our ongoing population assessment study. On this trip six surveys were completed, covering a wide expanse of Costa Rica’s rich and diverse habitats and updating our web of vulture knowledge by furthering our understanding of their winter movements. We also succeeded in confirming a collaboration with the non-profit Osa Birds: Research and Conservation, in which two annual vulture surveys will be completed by director Karen Leavelle and her crew.

Driving survey routes through Costa Rica

Driving survey routes through Costa Rica

There were many a day when the note taker (often me) remained in a constant state of scribble-frenzy as vultures swooped literally everywhere, and while neck cramps became my constant companion, they were worth the discovery that this year’s numbers were plentiful. In total, 2,785 vultures were counted! Turkey, black, and yes, king vultures were recorded as were other raptors, such as road-side hawks, black hawks, yellow-headed caracaras, and crested caracaras. The next step is to compare the numbers recorded in our 2019 surveys with surveys conducted in 2006. Hawk Mountain and its partners intend to repeat vulture surveys in many regions of the Americas in the next few years.

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 Costa Rica is part of an important geographical bottleneck that funnels migrating raptors to and from South America. During the early 2000’s there was a raptor count site called Kekoldi  located on an indigenous reservation close to Puerto Viejo. Kekoldi was run by Pablo from 2000-2006, and our own Dr. JF Therrien volunteered there as a counter, returning on this trip for the first time in sixteen years.

To revisit the site, we hiked from a lodge built and run by Sebastian Hernandez, a member of the Cabeca tribe, up to a tower built by Sebastian himself using trees from around his home. After climbing four flights of wooden steps our heads popped into sky surrounded by canopy, butterflies, chattering toucans, and eye level turkey vultures. Only moments later we caught the silhouettes of double-toothed kites, black hawks, white hawks, and a fascinating turkey vulture mimic, the zone-tailed hawk. All of these birds and more, in February.

Kekoldi and the Costa Rican migration corridor see one of the top five highest counts of migrating raptors in the world, and one of the most numerous peregrine falcon flights in the Americas. The Kekoldi tower was built with the intent of hosting visiting scholars, educators and enthusiasts from local communities and internationally. Regretfully, financial support became a limiting factor all too soon, and after a count of six years there were no longer resources to keep the tower manned each season, although sporadic counts are occasionally conducted. 

Many cutting edge studies are illustrating the need for understanding of species’ annual cycles, and this means investigating multiple hotspots along their journey. The Costa Rican Caribbean flyway is part of the migration pathway for many North American birds. Perhaps with greater outreach in raptor conservation, those with the knowledge and passion to start another count site may be inspired to do so. When that day comes, raptors throughout the Western Hemisphere will have higher chance of survival through their long migratory journeys in the years to follow because as we have learned, monitoring and education are a powerful duo that when used properly, can change the trajectory of conservation.

In addition to surveying vultures, Another intent of our visit to Costa Rica was to explore the possibility of promoting the importance of raptors within schools. Hawk Mountain is already partnering in Veracruz Mexico to promote environmental education and outreach and has been for more than 25 years. Our hope is to extend the raptor conservation message by providing materials and training throughout this critical flyway. 

There are approximately twenty schools near the Kekoldi count site that already receive outreach from the Talamanca-Caribe Biological Corridor, overseen by the country’s Ministry of Education. This organization is a well-established and respected facilitator of nature engagement for public schools in the area. During our visit we received a positive response from their education coordinator about the possibility of inputting a Hawk Mountain generated raptor component into their future programs. The intention would be to contribute materials such as children’s books, lesson plans, posters and interactive activities that would fit the needs of local schools, and prove useful within their community’s environmental reality. 

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JF and Pablo searching with binoculars from the tower.

JF and Pablo searching with binoculars from the tower.

On my final day at the tower I contemplated the strong undertow of the country’s natural history. Tropical creatures danced and shuffled by in erratic circles as we kept our binoculars skyward, waiting for a raptor to carve figure eights in the clouds above. Our hope is that one day this experience will be available to others, and that visitors will be able to engage in their very own sky clown moments, solidifying in their minds the majesty of the tropics and the beauty of the raptor world.

Please Pass the Machete: The Quest for the Harpy Eagle

Panama Eco-Tour Blog Part 2
Read Part 1 by Dr. Laurie Goodrich
here.

By Jamie Dawson, Educator
Hawk Mountain Sanctuary

It was dark in the thick Panamanian jungle, well before dawn. Before the howling monkeys rustled the vine-choked trees, the magical blue morpho butterflies flitted between flowers, and long before the creatures of the rainforest awoke to begin their daily balance of finding food without becoming food, gringos were stirring deep in the Darien, where the wild has not yet been tamed by man. They were a venturing on this mysterious Central American journey and forever bound in fellowship forged by the quest for the elusive harpy eagle.

 We loaded into our trusted van and excitedly sunk into our familiar seats, clutching dirty daypacks laden with our gear, water, and most importantly, copious amounts of dove chocolate. Fueled by strong coffee and the anticipation of fulfilling lifelong harpy dreams, we silently drove through the darkness.

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 Eventually our vehicle turned onto an unpaved dirt road, where two hardcore pickup trucks, seemingly straight out of Jurassic Park and decked out for off-roading safaris, were waiting to transport us to the next leg of our journey…the Chucunaque River. After rousing bumps and jolts, we arrived at the rural riverbank port cloaked in light rain, just as sun began to rise. There in the brown river floated our awaiting riverboat queens: two long, dugout canoes. After cautiously boarding, our canoe captains launched us down the longest river in Panama towards secluded harpy nesting grounds on the outskirts of the remote Sinai village.

 It was raining. We sat completely exposed to the elements without reprieve, as the water pelted us relentlessly for the entire three hour boat ride. I never expected to be cold in Panama. Furtive glances downstream revealed large flocks of disgruntled ibis dispersing in unison to escape the annoyance of our approaching vessels. Only one thought kept my chilled, rain-drenched despair at bay—chocolate. I watched the misty trees pass by and imagined the pleasure of gorging myself with the dove chocolates, tucked safely in my pack, upon reaching our destination.

Never has such an indomitable concentration of raptor enthusiasm been captured in quite delightful Argentinian form as our fearless leader, Sergio Seipke of Raptours. We left our canoes and followed Sergio through the thick banana fields, down the narrow trail carved out of the encroaching jungle. We had been given firm orders to strictly adhere to the trail and remain focused on the pursuit, as we were on a time-sensitive mission. Like a kid in a candy store, it took all of my willpower to resist the temptation to stop and explore the cornucopia of tropical life engulfing the trail.

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 With adept grace, our machete-wielding guides escorted us through deep, swiftly flowing streams as we pushed further into the lush heart of the forest. Finally, after mud, sweat, toil, and water-filled “water-proof” boots, we emerged victoriously to a small clearing hidden beneath the thick canopy. Draped in low-hanging, camouflaged netting and dappled with light and shadow, our eyes fell in awe on a majestic ceiba tree, prominently the highest point in the green expanse of the forest. Boasting superior views, the ceiba presents prime realty for nesting harpies, as few predators can summit the smooth, immense trunk.

 There it was at last, the harpy nest! Thick layers of strategically intertwined sticks lay nestled high in the ceiba canopy. With necks craned towards the clearing sky, we eagerly scanned the nest area for signs of the raptor residents. As the tense moments melted into minutes, our hopeful anticipation transformed into awkward disappointment; the harpies were nowhere to be seen. Despite our valiant efforts, we knew this unwanted outcome was always a possibility.

The female harpy eagle preening her feathers.

The female harpy eagle preening her feathers.

 But then, a large feather-crested head slowly emerged above the nest. To our astonished delight, the female harpy leisurely perched on an open branch, carefully preening and drying her feathers in the sun. The harpy’s mystical, whistle-like calls pierced the still, humid forest air, and her powerful wings shook rhythmically from the effort. Our guides quietly explained to us that she was calling for her mate to bring food. Mesmerized and elated by this privileged glimpse, we realized that the morning rain was truly a blessing. If the harpy hadn’t been wet from the early rain, she may not have left the security of her nest to dry off in the open sun.

 I could have watched the harpy forever, but the time had come to depart. We didn’t want our presence to deter the male harpy from returning to the nest with food, and we had a long journey back to our lodge, best made in daylight. I indulged myself with one last look through my binoculars and reluctantly pulled away from the blind to follow our group back to the canoes.

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 I’m no navigational genius, but somehow the trail looked different on the way back. I was sure we must have made a wrong turn, as our jungle trail was nowhere to be seen, and instead we carefully trudged through turbulent, waist-high water swiftly coursing its way through the understory. A flash flood had overtaken the region, and the water level of the river had risen over twelve feet in two hours. With this realization, a new heightened urgency hustled us to our canoes to depart while we still could.

 I stared incredulously at the swollen river. The canoes had been carried far inland by the rising water and were nowhere near where we had left them. Sediment, logs, and thick debris choked the fast moving current. We bravely boarded our canoes and braced ourselves for the perilous homeward journey. The air was tinged with electric excitement, as we straddled the thin line between adventure and real potential danger. The furrowed brows and distressed faces of our captains revealed the seriousness of our circumstances. Our reflexes were tested as we instinctively leaned into turns and quickly ducked under rapidly approaching riparian branches, hanging just inches above our canoe seats.

 At one point, we lost control as our canoe motors became tangled and clogged with debris. “Please pass the machete!” said one of the captain’s assistants who, against our protests, proceeded to jump out of the moving boat and scramble across the swirling, floating logs to cut away the debris from the motor. Entire unearthed trees swept past us ominously in the floods. I began to look around at my companions and silently assess their swimming abilities. Who would be able to survive and fend for themselves if we were to capsize?

 Finally, the motor was freed and we were moving again! But, wait - what was happening now? Our boat was moving backwards, and we were slowly reversing upstream, dodging collisions with oncoming hazards carried by the current. Utterly confused and equally concerned, I asked the captain in Spanish what was going on. Apparently, the captain’s jacket that contained the cash payments for the entire crew must have been snagged and caught on a branch, as it was now missing. So the captain logically informed me that we were now going back upstream in attempt to locate his lost jacket with the money. The group exchanged worried glances, and the HMS passengers called an emergency team meeting. We decided to pool our collective cash to replace the captain’s lost wages to avoid the unnecessary risk of traveling upstream. However, just as we were about to reveal our mutiny to the captain, against all odds, the missing jacket was spotted in the water. There it was, barely visible, caught on a branch submerged beneath the surface. The captain reached into the water, fervently pulled the soaking jacket until it snapped off the branch, unzipped a drenched pocket and triumphantly clutched a fat wad of dripping cash.

After an exhilarating trek back down the river, the HMS passengers are back on land.

After an exhilarating trek back down the river, the HMS passengers are back on land.

 Relieved to safely return to our port of origin, we disembarked our canoes in high spirits, cohesively bonded by the intense shared experience. The adventure continued as we mounted the open backs of the safari trucks for a bumpy bird-watching sunset ride. Delirious with fatigue and soaring on natural highs, Karen and I enthusiastically waved and yelled friendly “hellos” from the back of the truck as we passed by groups of children, and chickens, from the village. It had been, by far, one of the most amazing days of my life, made even more special by the humorous camaraderie and cherished friendships. It was truly unforgettable.

This blog is dedicated to Hawk Mountain volunteer, Karen Davidheiser, who accompanied us on several eco-tours in recent  years.

Thar She Soars!

By Zoey Greenberg, Science Outreach Leadership Trainee
Hawk Mountain Sanctuary

Many people associate the term “birder,” with images of a khaki-clad, hat-wearing, field-guide holding, binocular-wielding, mud-splattered nature enthusiast carrying a massive camera and an intense look on their face that says “SHHH…did you hear that?” Of course, there are many types of birders (I myself bird, and wear exactly one of these items), but to those unfamiliar with the lifestyle, a birder should be dawning the appropriate materials to claim the term. Imagine then, trying to explain to a police officer that the reason you are pulled over in someone’s lawn staring at their house with binoculars is because you are, in fact, birding. You are not wearing khaki, there is no mud on your pants, but you do have a camera. He does not believe you. The camera does not help your case. This is what we call a predicament.

Zoey scans the skies from the roof of her car.

Zoey scans the skies from the roof of her car.

Such a circumstance is one of the amusing side effects of conducting road surveys to monitor vulture populations. Hawk Mountain has been doing this over the last 12 years, gradually collecting baseline data on both turkey and black vulture populations throughout the Western Hemisphere. Our protocol involves following roads that are least likely to induce rage from other drivers (we drive 40 miles per hour, and frequently swerve to hop out and count birds on cell towers, sometimes climbing the car for optimal vantage points). We need at least two people, a reliable vehicle, and enough time to accurately gather data. Ideally we conduct these surveys every 10 years in both summer and winter, for each site. Compared to other research projects, road surveys are a good bang for the buck because they are relatively cheap to conduct but provide us with critical baseline data on a group of animals that are crucial to the health of our environment. In total, Hawk Mountain has conducted over 50 vulture surveys in 9 countries.

Many of you may be aware of the vulture crisis that has occurred in the Old World over the last two decades, but I’ll offer a reminder by first reviewing the numbers: out of the world’s 22 species of vultures, 16 are spread among Africa, Asia and Europe. 11 of these have recently become at risk for extinction in our lifetime. Some species have experienced a 99% decline since the late 1990’s.

Courtesy of BirdLife International

Courtesy of BirdLife International

With the combined effects of persecution, poisoning, drug-induced kidney failure, and harvesting for parts, the Old World has faced a fast-acting recipe for vulture disaster.

In Asia the primary cause of these mass die offs is a pain killer for cattle called Diclofenac that is ingested by vultures feeding on livestock carcasses.

In Africa the main threat is poisoning. In Europe, Diclofenac is still legal, and declines are anticipated if policy-makers don’t act quickly. There is a less harmful alternate drug available that offers the same therapeutic effects for a similar price, but so far, new legislation has not been passed.

Griffon vultures live on all three continents. Photo by Emmanuel Keller

Griffon vultures live on all three continents. Photo by Emmanuel Keller

Prior to the declines recorded in Asia and Africa there was no reliable baseline knowledge on the population size of affected species, meaning estimates of loss are likely conservative. Consequences from loss of vultures have included an increase in rabies cases due to a higher prevalence of wild dogs, as well as the spreading of diseases that were previously processed in the gut of these under-appreciated scavengers.

This is a perfectly heart breaking example of how human bias towards the most lovable species can sometimes harm those that float under the radar. To make this mistake once is somewhat forgivable. To make it twice is not.

This is why I believe Hawk Mountain’s vulture surveys are crucial. Vultures have been misunderstood and ignored, and while there have been commendable efforts to remedy this issue in Asia, Africa and Europe, we still have work to do in the Americas. We need to be proactive in deciphering how many vultures there are, fully understanding their role within our shared ecosystems, and proving their value to the public. Science alone cannot prepare us. The integrity of our future environment requires that we establish a culture of appreciation around vultures that will allow them a seat at the ecological table.  

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Okay, that’s the heavy part. Now, let’s focus on the fact that in the U.S., our vulture glass is half full. Our last survey resulted in a count of 979 vultures, between five routes in Georgia and Florida. Ten years ago, this same survey produced similar numbers, proving stability exists within that region. We continue to witness healthy numbers of black and turkey vultures throughout Pennsylvania and much of the eastern United States. This may not be the case in Central and South America, though our upcoming surveys in Costa Rica, Panama, and Argentina will hopefully add to our body of knowledge on population size and trends.   

On one of our final days in Florida, we spotted a group of vultures circling something yellow and indistinguishable. A scout landed and tore into whatever “it” was. After scanning with binoculars, exchanging excited hypotheses, and crossing a treacherous road, we discovered that the mysterious yellow “entrails” were no more than the sad remnants of a Happy Meal. This not only confirmed my suspicion that vultures are closet vegetable lovers but also reminded me that scavengers are adaptive problem-solvers. Black vultures in Central America drag coconuts into the middle of the road and wait for cars to pulverize them into a meal. We hear of crows and ravens using tools, eagles stealing fish from other birds, and raccoons breaking into, well…everything. Scavengers are scrappy, and vultures are no exception. This gives me hope that with support, they will adapt to our ever-changing human dominated environments.

As we watched the sun set behind the french fry frenzy, I felt optimistic that with continued monitoring my innovative feathered friends would have many more happy meals.  

Soaring to Panama

Panama Eco-Tour Blog Part 1
Read Part 2 by Jamie Dawson
here.

By Dr. Laurie Goodrich, Director of Long-term Monitoring
Hawk Mountain Sanctuary

Panama.  I am finally here.  Since I was a university student I have longed to visit here, enticed by reading the landmark tropical ecology studies that occurred here at sites such as Panama Canal Zone, Pipeline Road, and Canopy Tower.  Later on, as a hawkwatcher, I read of Ancon Hill and the clouds of Swainson’s hawks and turkey vultures swirling above Panama City, and a new “bucket list” place was born.

On October 19, five of the Hawk Mountain 2018 Panama eco-tour members arrived at night to await the start of the Hawk Mountain tour to Panama the following day, with Raptours and raptor expert/former Hawk Mountain trainee Sergio Seipke.  Arriving in the dark, my first impression of Panama City was, ”…Wow, this is larger than I imagined.”  The city lights illuminated towering skyscrapers, boldly lit casinos, and bustling streets.

Bird-watching by the pool, photo by Laurie Goodrich.

Bird-watching by the pool, photo by Laurie Goodrich.

We gathered near the pool for bird-watching and breakfast the next morning.  Sergio pointed out a three-toed sloth sleeping in the tree next to the porch, and soon small flocks of crimson-backed tanagers, thick-billed euphonia, and other tropical birds flitted around us.  By 7:30 am, hundreds of broad-winged hawks rose up over the hotel, circling low and streaming to the northeast.  Swainson’s hawks, Mississippi kites, and black and turkey vultures, joined the flow along with short-tailed hawk and hook-billed kite.  Hundreds of common nighthawks glided overhead along with clouds of barn and cliff swallows as well, all possibly having passed over Pennsylvania in weeks past. 

Kettling broadwings and other raptors, photo by Diane Allison.

Kettling broadwings and other raptors, photo by Diane Allison.

During the late morning, continued streams of broad-winged hawks and turkey vultures sailed overhead.  Patty, a female Broad-winged Hawk from northwest Pennsylvania that we had satellite-tagged in 2016, had roosted just 11 km west of our location on the night before. I was sure she soared above us that morning amid the 50 thousand broadwings we tallied over our hotel, and her satellite-tracked pathway confirmed my suspicion!

The following morning the full 14 member group met up with our Panama bird guide for the tour, Domi, Domiciano Alveo, who along with Sergio of Raptours made sure we saw every bird. After a morning of watching tropical kingbirds, chachalacas, and other new birds, we spent the morning hawk-watching within view of the Panama Canal and the famed Ancon Hill. We watched streams of birds rising off the hills west of town and flying towards us. Contrary to our North American bias, south-bound raptors fly northeast to traverse Panama City and avoid crossing water.

Aplomado falcon perched in tree, photo by Brian Moroney.

Aplomado falcon perched in tree, photo by Brian Moroney.

The next day  we explored the impressive Miraflores Locks- Panama Canal museum.  We stood on a fourth floor deck overlooking massive freighters inching their way through the locks. From the deck, we spotted a king vulture soaring and a bat falcon hunting from the Canal Zone light fixtures.

For the next few nights we stayed at the Canopy Lodge, an amazing eco-lodge immersed in forest aside a fast-flowing stream with fruit feeder trays and hummingbird feeders adjacent to large open deck.  Experienced guides lingered to point out birds and a comfortable sitting area welcomed us to never leave.  During our days we explored the surrounding region and visited the Pacific Ocean.  Small clouds of raptors were seen nearly everywhere in the central mountains.  On the Pacific slope, we had one incredible view of an aplomado falcon perched alongside the road and savannah hawks hunting with egrets in wet meadows.  Other birds included a roadside hawk, crane hawk, and white-tailed kite. 

We then moved to another famed eco-lodge, the Canopy Tower.  Here we were greeted by well-known nature and bird guide, Carlos Bethancourt, who along with the staff treated our group as kings and queens.  The Canopy Tower was built in 1960s as part of the radar defense system for the Panama Canal and was also used to detect drug-carrying planes in the 1980s. In the 1990s it was transferred to visionary Raul Arias de Para who renovated it into a center for neotropical-rainforest ecotourism.  Today the Tower has a hawk-watching deck and hosts bird-watchers in overnight rooms set into the sides of the circular tower.  Rain was a daily companion for us and dampened some of our hawkwatching, however side trips were amazing and included a visit to the famed Pipeline Road, Rainforest Discovery Center and a boat trip on the Canal. 

I gained a new appreciation for the trials of migration through Central America as each day rain blocked flights or kept flocks of hawks fighting for lift. After a cloud burst rain amid the forested hills, we watched an immature broad-winged hawk plummet into the treetops to perch, drenched and wet and looking thoroughly dejected.  As sun tried to emerge, it spent 40 minutes trying to preen its feathers before it finally circled up to try to migrate again.

Geoffroy’s Tamarin monkey, photo by Brian Moroney.

Geoffroy’s Tamarin monkey, photo by Brian Moroney.

Tropical Mammals were a treat to see. At the Tower, Geoffroy’s Tamarin monkeys lingered near the upper deck staring at people, hoping for banana gifts, while white-nosed coati and howler monkeys occasionally passed by. White-faced capuchin troops were seen occasionally and three-toed sloths were spotted nearly every day. 

Each morning an optional pre-dawn gathering occurred outside the Tower, complete with fresh-brewed coffee and tea. Sergio and Domi stood quietly in the dark attempting to call in one of the elusive forest falcons. Mostly the forest was quiet until dawn wakened the hummingbirds to hover at nearby feeders.  On the last morning we met at 5:30 am hoping for the best.  After about 20 minutes, suddenly Sergio leaped to his feet and motioned us off the deck to the driveway below. Soon, not one but all three forest falcon species were heard-- collared, slaty-backed and barred forest-falcons!  For me hearing those rare species was the icing on the cake for a wonderful trip.  For the main tour we tallied 39 raptor species and 253 total birds, despite enduring torrential downpours on part of every day.  We enjoyed amazing views of broad-winged and Swainson’s hawks kettling over the rugged hills of Panama, and, I checked off a lifetime bucket list place.

Group shot taken in the Canopy Tower.

Group shot taken in the Canopy Tower.


This blog is dedicated to Hawk Mountain volunteer, Karen Davidheiser, who accompanied us on several eco-tours in recent  years.

Stay tuned for Part 2, which will tell the dramatic tale of the extension portion of this eco-tour!

Irruptions and Innovation

By Zoey Greenberg, Science Outreach Coordinator
Hawk Mountain Sanctuary

Stella, a snowy owl tagged by Project SNOWstorm earlier this year.

Stella, a snowy owl tagged by Project SNOWstorm earlier this year.

In 2007, Dr. JF Therrien deployed 12 transmitters on snowy owls on Bylot island in the Canadian Arctic. Snowy owls, like other raptors, can be difficult to monitor due to their territoriality and low densities. Arctic-breeding raptors typically establish nesting sites in remote locations, adding to the logistical dilemma of gaining insight into their life history traits, and the role they play within the Arctic ecosystem.

Satellite transmitters, citizen science, and long-term life history studies are extremely valuable tools that allow researchers to examine the movement ecology of birds, including snowy owls. Mixing and matching these tools can open doors to compelling scientific questions, and in the case of Therrien’s snowy owls, has resulted in papers covering a range of topics. New information on survival, reproduction rate, dispersal of adults, irruptions and winter movements are among recent Hawk Mountain publications that were made possible through this type of innovation. 

Two such papers were led by former conservation science trainees, in collaboration with others, including Dr. JF Therrien. These papers delved into the mystery of snowy owl irruptions, defined as the “massive movement of individuals over large distances, associated with large fluctuations in food supply.” Some of us have been lucky enough to see a snowy owl in Pennsylvania, on those rare winters when the birds venture further south than usual. I myself drove two hours to catch a glimpse, and I will never forget the sight of that owl hunkered down in the middle of a field, glittering in evening light. As I drove away, I couldn’t help but wonder; what brings them here?

Two primary hypotheses have been proposed to explain irruptions; the “lack-of-food” hypothesis suggests that snowy owls leave their normal wintering grounds because of food shortage in certain years. This implies that the snowy owls we see in Pennsylvania should be in poor shape, and likely close to starving. The alternative “breeding success” hypothesis instead links irruptive movements to a surplus of food on the breeding grounds.

A snowy owl that was spotted in a local PA field last year.

A snowy owl that was spotted in a local PA field last year.

Snowy owls specialize in lemmings, a prey resource that occurs in pulses, due to their population dynamics. One year there may be a plethora of lemmings scurrying around the tundra, the next year very few, due to high predation and other factors. Lots of lemmings means lots of chicks, which means lots more owls. The breeding success hypothesis implies that the reason we see snowies in Pennsylvania is because following a high lemming year, there are so many owls dispersing at the end of the summer that some young birds push south.

To add depth to our knowledge of irruptions, Teja Curk, a conservation trainee from 2016, assessed the body condition (mass relative to size) of snowy owls during both irruptive and “regular” years. Teja assessed body condition of snowies on both regular (Great Plains) and irregular (Northeaster North America) wintering grounds, to see whether the birds we see during irruptive years are, in fact, starving. She found that most owls (male, female, juvenile and adult) were in good shape during irruptive years and even discovered that body condition was better on the bird’s irregular wintering grounds. “Good shape” in this context varies depending on sex and age of the bird, however less than 2% of the owls approached the weight threshold that would deem them a starving bird. Her results provide support for the breeding success hypothesis.

Pablo Santonja and Irene Mestre, trainees from 2015, looked specifically at the age of the birds found south during irruptive years. Their results supported the same hypothesis, showing that the majority of owls (up to 90%) seen in eastern North America are juvenile birds, meaning they are less than 1 year of age. As with some other migratory species, the more dominant birds within a population don’t move as far. Adult snowy owls often out-compete young birds, so it makes sense that in a year where adults are laying up to 11 eggs, some of those young owls will need to leave to avoid competition from more successful, experienced adults.

Bylot Island, where the Hawk Mountain team tagged and tracked several snowy owls.

Bylot Island, where the Hawk Mountain team tagged and tracked several snowy owls.

This leads to an interesting point: perhaps these two competing hypotheses are not, as Teja notes in her paper, mutually exclusive. After a highly productive lemming year, many lemmings will be eaten due to a surge in predator numbers, and therefore the next year could produce low lemming numbers. If this happens, snowy owls could be forced to look elsewhere for food. So, it turns out, that both a surplus of food and a lack of food seem to play a role in the patterns of movement among snowy owl populations.

If you ask me, these papers are a beautiful example of the scientific method at work; formulating ideas, testing those ideas, and polishing the conclusions in pursuit of certainty. Hats off to our trainees and their collaborators for hard work and intriguing findings. Teja is currently at the Max Planck Institute for Ornithology in Germany pursuing a PhD. Pablo is living in Spain, and Irene is now returning from three years in Australia.

Both of these papers utilized a data set resulting from a 25 year-long study in which live snowy owls were weighed, sexed, and aged. Christmas Bird Count (CBC) was also a valuable asset in both studies. For those of you unfamiliar with CBC, every winter thousands of volunteers gather together on the same day, collecting bird records within a territory and submitting them to a database that provides an impressive summary of which birds were seen, where, and how many. These papers demonstrate the utility of both citizen science and long-term studies, and in a rapidly changing world, this cross-pollination of resources is critical. We are very proud of our trainees for their hard work, and grateful to citizen scientists around the globe who give their time to participate in the expansion of our raptor knowledge.

Gaining a holistic understanding of an ecosystem requires acknowledgment of moving parts within, not separate from, the whole. Hawk Mountain’s research is part of several collaborative efforts to better understand the role of snowy owls within the big picture, including Project SNOWstorm and the Bylot Island Ecological Studies and Environmental Monitoring.  

Future projects will include building a model that combines reproductive and mortality rates to assess population trends of snowy owls. This past August, three transmitters were deployed on chicks before they left their breeding grounds. Investigating the movement patterns of these birds will hopefully allow for a comparative look at owls throughout the Eastern tundra, Western tundra, and those in between.

Check out Project SNOWstorm’s website (including a blog written by J.F Therrien on the most recently tagged snowy owls in Barrow, Alaska, as well as interactive maps): projectsnowstorm.org/posts/tracking-young-snowies-in-the-arctic/

Trainee to International Conservation Pioneer

By Alfonso Godino, Research Associate
Hawk Mountain Sanctuary

The cinereous vulture was extinct in Portugal as a breeding species at the end of the 20th century, but in 2010 a new colony was established in Tejo Internacional National Park, in the eastern limit of the country and close to the border with Spain.

This colony now hosts 18 breeding pairs, and no studies were done before out of the annual breeding monitoring implemented by the Natural Park’s staff. Due to this lack of information, and being the main population in Portugal, our goal is to get information about the dynamic of this colony. Thus, the first step is to study the juvenile dispersion and the potential causes of mortality of this population.

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During the summer of 2018, eight nestlings were tagged with GPS-GSM transmitters, supported by Hawk Mountain Sanctuary and the Spanish electric company ENDESA. This support will continue during 2019, with the goal to increase the number of birds in this study and to get more accurate and representative information.

All this information will be shared with the Natural Park’s managers, with the objective to facilitate them the conservation and management of the colony, since all the nests of this colony are in private estates inside the protected area.

Alfonso with a tagged vulture outside of the HMS Acopian Center for Conservation Learning

Alfonso with a tagged vulture outside of the HMS Acopian Center for Conservation Learning

But how did HMS reach Portugal? During 2009, I was at Hawk Mountain as a trainee. I was an enthusiast in vultures’ conservation, and HMS offered to me the amazing opportunity to trap turkey vultures and to use wing tags for the first time in my life. But for me, the most impressive was to get access, for the first time in my life, to the huge amount of information about raptors in the Sanctuary library. I spent many days reading papers and copying a lot of info to bring with me after my traineeship. From that time, I was interested in vultures’ juvenile dispersion but never had the opportunity to be involved in a project with this objective.

And again, after almost a decade, a causality joints me one more time to HMS, but this time in Portugal, not in Pennsylvania.

In this new cinereous vulture’s project, HMS is more than a sponsor offering GPS devices. From the beginning of the proposal to HMS, its permanent support and fast reply have encouraged me to work in this project, especially during the hard times of preparations, authorizations, organization, etc. I am sure that the presence of HMS in the project has been a motivation to other bodies to participate and be part of it. The result has been the creation of a task force, where raptor conservation and research organizations such as HMS, a private company such as the Spanish electric company ENDESA, and the government of Portugal, are in a narrow collaboration to study and protect the cinereous vulture in this colony.

Now, with the vultures sending throughout the transmitters lots of daily data, it is time to enjoy learning how these vultures move around the Iberian Peninsula and, who knows, maybe one of them cross the Gibraltar strait toward Africa and offer us new and unexpected information about the movements of this species to sub-Sahara regions!

Check out this video of Alfonso and his team tagging and releasing a cinereous vulture!

Across the Pond with Raptor Care Rock Star

By Rachel Spagnola Taras, Senior Educator
Hawk Mountain Sanctuary

Nearly a decade ago, Jemima Parry-Jones (JPJ), Director of the International Centre for Birds of Prey (ICBP) located in Newent, Gloucestershire, United Kingdom, answered an e-mail I sent to her hoping to gain insight on captive raptor management. Not only did JPJ promptly and thoroughly respond to my questions, she insisted that I visit her facility. With the generous support of Hawk Mountain Sanctuary friends Brian and Sandra Moroney, I completed my educational journey across the pond earlier this season to benefit our feathered educators and the volunteers and staff who work together to maintain best practices in raptor care management at Hawk Mountain. Education raptors help to connect learners of all ages to conservation with an up-close look at species that serve a vital role in our ecosytems worldwide. 

Jemima Parry-Jones and a barn owl welcom school children to ICBP.

Jemima Parry-Jones and a barn owl welcom school children to ICBP.

Located in the quaint English countryside, ICBP oversees nearly 300 birds of prey, including a diverse workforce of owls, eagles, vultures, kites, hawks, falcons, and harriers. During my stay, I was treated to a grand tour of the entire facility. Open to the public 7 days per week, 10 months of the year, visitors have the opportunity to see raptors on display in a zoo-like static setting and during multiple free-flighted training sessions throughout the day. During these flying demonstrations, ICBP trainers connect visitors of all ages to a fast-paced, exciting look at natural history in action.

One highlight of my visit was participating in training several  yellow-billed kites by cuing birds to fly over the field in front of visitors and signaling them to return, tossing meat straight up in the air to emulate their natural behavior of grasping prey in flight. Although I do not consider myself athletic, there’s nothing like being watched by countless visitors who are glued to your every move while one of the most famous falconers in the world is narrating and evaluating your meat throwing abilities. With the supportive direction of JPJ, I felt like an Olympian.  

An ICBP staff member monitors the weight of a white-tailed sea eagle.

An ICBP staff member monitors the weight of a white-tailed sea eagle.

In addition to shadowing the husbandry and training of some of the world’s largest and endangered raptors, I learned new techniques and skills to improve communication through body language and clear cues when working with animal colleagues. While working with a massive white-tailed sea eagle, I honed my ability to remain perch-like to provide a stable and trustworthy roost. If you see me lifting weights, you’ll understand why I want to build and maintain a strong  and stable resting place for a bird who weighs over ten pounds.

 Sadly, when visiting the on-site rehabilitation hospital building, I learned more about real-time conservation challenges like the direct persecution of raptors in the community. Unlike North America, migratory birds are not legally protected and are perceived as competition for resources such as small game.  I had the opportunity to meet with law officials who were inspired by Hawk Mountain Sanctuary’s rich history thanks to pioneer conservationists like Richard Pough and our own founder, Mrs. Rosalie Edge.  

On this side of our shared Atlantic Ocean, I remain proud to represent the world’s very first refuge for birds of prey and to help advance our mission by sharing our story and the need for continued research and education worldwide.

Help support our raptor care and public raptor education efforts by donating or becoming a member today.

Informally Influential

By Zoey Greenberg, Science Outreach Coordinator
Hawk Mountain Sanctuary

Zoey presenting during the PAMLE 2018 Conference

Zoey presenting during the PAMLE 2018 Conference

This October, HMS Director of Education Erin Brown and I presented at the 2nd annual conference for PAMLE, the Pennsylvania Association for Middle Level Education. The keynote speaker, Dave F. Brown, co-author of the book What Every Middle-School Teacher Should Know, started the day off with a potent analysis of how the average preteen views the world. Incorporating neuroscience, he made a compelling case for increased compassion towards adolescents and the importance of cultivating supportive learning environments in middle school classrooms.

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Dr. Brown also highlighted the importance of identity development, reminding us that middle school students are discovering who they want to be and what they value. This point stuck with me for the remainder of the day. I tried to remember what it felt like to be a seventh grader and found myself in agreement: the first memories that resurfaced were of social belonging, and attempts to carve space for myself in an ocean of others.

Towards the end of my own presentation at the conference, I received a comment from a teacher that drove my contemplations deeper. He told me he has many female science students who begin with enthusiasm but almost always fade away from science because they claim it’s associated with boys and technology. This got me thinking about ways in which informal education has a role in the presentation of science, not just as a career, but as an exploration of identity.

Many of us would agree that science is largely defined by the scientific process, which includes inquisition and curiosity. Some, including myself, would say that passion is often an important catalyst for scientific discovery. Schools work hard to prepare students for their future, as they should. However, teachers face a plethora of challenges and deadlines that can sometimes limit their creative methodology when introducing an entire field of study. Science and technology have quickly become buzz words of the future; however, I would argue that the definition of science in this context is related heavily to human progress and less to other important avenues such as environmental protection or the classically termed “dying breeds” of natural history and zoology.

Zoey working with students from the Swain School in Allentown, PA on the newly developed HMS Black Vulture curriculum.

Zoey working with students from the Swain School in Allentown, PA on the newly developed HMS Black Vulture curriculum.

It is within this gap that I feel that Hawk Mountain plays a huge role. We create educational materials for the classroom that give teachers options for how to design their own framework of science. We align these lesson plans with standards, include the most up-to-date raptor science, and offer training to teachers whenever possible. In this way, I believe that we are paving a beautiful path towards an inclusive definition of the word “science” that can be offered to young students who may simply identify as lovers of wildlife but aren’t sure how to weave this piece of themselves into their academics.     

If Hawk Mountain staff had come into my 7th grade classroom and told me that there were real live adults that studied birds of prey for a living, my jaw would have hit the floor. Part of the reason I feel such pride in this organization is because we expose the young and the old to a breathtaking dimension of the natural world, and we put effort into reaching those that cannot make it to our site. I regretfully shied away from science in middle school, and I want to acknowledge the role that informal education can have in welcoming adolescents to a rewarding and impactful field. Raptors provide an intriguing route into the realm of science and Hawk Mountain is well equipped to assist teachers on the road to creative instruction. 

A vulture roost in Reading, PA, that Zoey observed during her time as an HMS conservation science trainee.

A vulture roost in Reading, PA, that Zoey observed during her time as an HMS conservation science trainee.

Erin and I were the only non-formal presenters at this conference, and I was heartened to see that our presence was valued. I have immense respect for the consideration that attendees at this year’s PAMLE conference showed for their student’s well being, by assessing ways to enhance how we, as a community invested in youth, can encourage student growth. Our world is brimming with amazing teachers, and I feel optimistic that through partnership between informal and formal educators, innovative education has no limits. Trust me, even a turkey vulture roost can become a world of discovery with the right attitude and freedom to set the stage.

Tips for Conference Confidence

By Zoe Bonerbo, Summer 2018 Education Intern
Hawk Mountain Sanctuary

Zoe (front left) joined by fellow Hawk Mountain staff, trainees, and board at the HMANA 2018 Conference.

Zoe (front left) joined by fellow Hawk Mountain staff, trainees, and board at the HMANA 2018 Conference.

Last month I attended my first professional conference, the HMANA (Hawk Migration Association of North America) conference in Detroit, Michigan! The conference was focused on raptor migration research and education. While it was initially nerve-wracking, by the end of the three days I didn’t want to leave. I therefore decided to I compile a list of tips for anyone who might not know how to prepare or what to expect their first time attending a conference.



1)      Ways to attend

Conferences can be expensive but also very rewarding! For my first conference, I volunteered part time in exchange for free registration. Try contacting the host organization to see if they have any opportunities available. Additionally, if you are a student, look into any scholarships your school may provide for professional development and conference travel. This can help reduce costs.

2)      Confirm and double-check all reservations

Often times flights are delayed (mine was several times), or reservations could be booked under a different name resulting in confusion at the hotel service desk. Either way, once you know you’re going, make sure to communicate your plans to any other parties involved. Everybody will be much more reassured knowing everyone is on the same page!

An American kestrel introduced during one of HMANA’s presentations.

An American kestrel introduced during one of HMANA’s presentations.

3)      Do a bit of background research

Find out who will be presenting and on what topics. Read a bit about the speakers’ backgrounds and find sessions you think you’d be interested in listening to. Often, very technical vocabulary is used in presentations. If you don’t know much about a topic and want to go to the session anyway, try to read a bit of general information on the subject so you know you’ll be able to follow along! Also, make sure you know the general outline of the conference schedule (while you don’t need to memorize it, it is helpful knowing the start times of major events throughout the day).

4)      Start small

If you have the option, look for a smaller conference to start out. One of the reasons I felt I had such a great time at the HMANA conference was because it wasn’t overly packed. I wasn’t overwhelmed with too many events or too much information. There was a more casual approach to dressing, and the general vibe was much more intimate and relaxed. It also gave me the opportunity to talk with many of the people there, which leads me to my next point…

Zoe (left) with HMS Conservation Science Trainee Amanda Woolsey.

Zoe (left) with HMS Conservation Science Trainee Amanda Woolsey.

5)      Don’t be afraid to start conversations! 

Many of the people attending are professionals and experts in the field, which is both inspiring and intimidating. However, don’t go in with the expectation that you need to network. Networking is very useful, but can often lead to stress and disappointment. Instead, simply try to learn from both speakers and those around you. Showing genuine interest can build relationships and lead to potential collaborations down the road. I was able to passionately discuss and speak with several individuals who lived in other countries, which greatly broadened my perspective and knowledge about global wildlife.

6)      Let yourself rest

Lastly, while it’s important to take advantage of opportunities, it’s also alright to take breaks. Packing in all the events or speakers you want to hear may seem fun at the beginning but could end up burning you out by the end. It’s okay if you skip an event or two to recharge. The dynamic of conferences can be intense, so let yourself be flexible. This way the events you do attend will be much more enjoyable!

Now you can embark on your first conference adventure! Hopefully, with a little preparation your first conference will be a big success.

 I would like to extend a big thank you to Jane Ferreyra, Executive Director of HMANA and Erin Brown, Director of Education at Hawk Mountain Sanctuary for greatly assisting me in attending this conference!