science trainee

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/

Partnership of Promise

By Zoey Greenberg, Science Outreach Coordinator
Hawk Mountain Sanctuary

Physiology: a branch of biology that deals with the functions and activities of life or of living matter (such as organs, tissues, or cells) and of the physical and chemical phenomena involved.
— Merriam-Webster
Hawk Mountain’s American Kestrel Poster displayed on Cedar Crest College lab door.

Hawk Mountain’s American Kestrel Poster displayed on Cedar Crest College lab door.

 On October 23, assistant professor Allison Cornell visited Hawk Mountain from Cedar Crest College to provide a seminar on the physiology of developing American kestrels, emphasizing the role of the Sanctuary’s nest box program in her research. Collaboration between Dr. Cornell and Dr. JF Therrien, senior biologist at Hawk Mountain, began in 2017 and has resulted in exciting science concerning a widely-appreciated falcon species that has been experiencing declines nation-wide.  

 In her seminar, Dr. Cornell highlighted the importance of an integrative approach to understanding the ecological context of a species, stating a cherished quote of hers:

 Behavior is observed physiology.
— Vincent Dethier.
Life History Diagram

Life History Diagram

 As a physiologist, Dr. Cornell’s methods include the assessment of internal as well as external factors that could influence the survival and overall condition of developing birds. Her past work has included assessing the relationships between nestling condition and oxygen storage capacity and identifying how factors such as timing of breeding are related to developmental cues in starling chicks. This type of research adds color to the bigger ecological picture, allowing us to learn more about why birds exhibit the behaviors they do, and how this relates to their overall survival. Factors like pectoral muscle mass, aerobic capacity, red blood cell count, and wing area are just a few telling descriptors that can shed light on what prepares a bird to leave the nest. Turns out, there’s more to it then being kicked out by your parents! 

 For Dr. Cornell, Hawk Mountain’s kestrel nest box program has been instrumental to the success of her research. Nest boxes provide an opportunity to observe kestrel development in a natural setting rather than in a lab where results can be compromised by the lack of true environmental influences. In addition, the nest box program has done the ground work of establishing relationships with landowners, which allows for Dr. Cornell’s research to be conducted in a kestrel-friendly culture.

 Hawk Mountain sees immense value in partnering with an experienced researcher who has the time and passion for conducting good-quality science using Hawk Mountain’s long term data set and putting in the field time to monitor boxes. In addition, trainees and students from both sites are benefiting from the academic opportunities included in this project. Mercy Melo, a student at Cedar Crest, and Jen Houtz, a former conservation science trainee, are both currently involved in the work with Dr. Cornell.

Through the deployment of nest cams and this thorough approach to ecology, Dr. Cornell has given students access to several thought-provoking research topics, including how physiology traits change across nesting period and whether “dead beat” falcon dads have an impact on the physiology of their young. This work has the potential to fill information gaps and provide necessary context to the kestrel decline.

Map from Raptor Population Index showing population status in different regions. Red arrows signify significant declines.

Map from Raptor Population Index showing population status in different regions. Red arrows signify significant declines.

 Collaboration between Hawk Mountain Sanctuary and Cedar Crest College has opened doors to new research, and has also given young professionals the chance to step into raptor ecology with resources that are not always easy to come by: a long term data set, accessible observation sites, and supportive advisors from neighboring institutions. This is a clear win-win for raptor conservation and one that Hawk Mountain is thrilled to be a part of.

 - - -

Click here for more information on our kestrel nest box program, or see below for Allison Cornell’s.

Variation in developmental trajectories of physiological and somatic traits in a common songbird approaching fledging. Journal of Experimental Biology. Cornell A, Williams TD. 2017-10-13

Experimentally-increased male social behaviour has no effect on female breeding phenology and performance. Animal Behaviour. Cornell A, Hou JJ, Williams TD. 2017-01-23

Double-brooding and individual quality in a highly synchronous songbird population. The Auk. Cornell A, Williams T. 2016-01-13

Physiological maturity at a critical life-history transition and post-fledging flight ability. Functional Ecology. Cornell A, Gibson KF, Williams TD. 2016-10-04

Mid-winter temperatures, not spring temperatures predict breeding phenology in the European starling Sturnus vulgaris. Royal Society Open Science. Williams TD, Bourgeon S, Cornell A, Ferguson L, Fowler M, Fronstin RB, Love OP

Monitoring Migration in Eilat, Israel

By Ana De Osma Vargas-Machuca, Autumn 2016 Conservation Science Trainee
Hawk Mountain Sanctuary

A month ago I came back home from my Israeli adventure, where I have been monitoring the spring raptor migration in Eilat, a dream came true.

This all began in 2011, when I met Re'a Shaish while volunteering in the Migres Program in Tarifa, Spain. He is an Israeli guy who was extremely passionate about birds, and at only 19 years old was able to identify every single species of raptors flying over us. He told us about Eilat and the migration there, and since that moment Eilat had been always on my mind.

Last year we met again in Extremadura for a couple of days, where he was assisting Yoav Perlman with his field work, and both of them told me again about the spring migration in Eilat. I was working as a biologist in Spain, but it wasn't anything related to conservation biology. I greatly missed being in the field, so at the end of the year I arranged to be off from work in the spring and contacted Noam Weiss (the director of the IBRCE) to apply for a position as a counter in the raptor team. When I got his reply telling me that I was accepted, I was elated.

So there I was at the end of January, flying to Eilat, watching through the window the beautiful Negev desert, getting goosebumps and feeling excited for all of the experiences to come.

Counter station in the Eilat Mountains. 

Counter station in the Eilat Mountains. 

We were two teams of volunteers: the raptor counters, working mainly at the stations in the mountains, and the ringers and guides, working at the sanctuary.

The first of February was the first day of the count. The count was conducted by four of us (Daniel, from UK; Gaidis from Latvia, Ragnar from Denmark, and myself), divided in two stations, Low Mt. and High Mt. Station, both of them in the Eilat mountains, close to the Egypt border.

Ana in the "office."

Ana in the "office."

At the beginning of the season, the migration was still very low, so those not counting would have the chance to go to the sanctuary to assist with other work or to just bird around. I remember the first day being at High Mt., and even if I had no birds migrating, I felt so grateful for just having the chance of being there, in such a beautiful office, with Jordan on the east, the Red Sea and Saudi Arabia in the south and Egypt in the west.

Some brown-necked ravens, Tristam's starlings, two dessert larks, a hooded wheatear, and a very nice juvenile white crowned wheatear were our regular visitors who sat at the station and kept us company. On those days of counting steppe eagles in February, there were some amazing days with birds flying overhead, very close to us. Such incredible creatures in that stunning landscape... I was happy no matter what weather I had, how many eagles were migrating or how many people visiting; being there was just amazing.

Ana with the rest of her team at Eilat. 

Ana with the rest of her team at Eilat. 

In February we would finish work before sunset and still have time to go to the beach for some snorkeling before the light was gone. We lived in the Field School, right in front of the beach near the Taba border with Egypt, so coming back home from the mountains and walking to the beach with the guys for some snorkeling was our daily afternoon routine. We found some spots with well-protected coral reef and snorkeling there with all of those beautiful fish was delightful.

Ana in the Arava Valley near Hatzeva during the Arabian warbler survey.

Ana in the Arava Valley near Hatzeva during the Arabian warbler survey.

First week of March, I was selected together with Anton (a Danish ringer) and Ohad (Israeli birdwatcher) to be part of the Arabian warbler survey taking part in the Arava Valley, close to Hatzeva (2 hours north to Eilat). This survey was very important, as there is very little information about the species, and the first and last survey was on the 1980, conducted by the SPNI. We walked around 10-15 km everyday in the desert, looking for Arabian warbler territories but also recording every bird species around, but this incredible opportunity of going where few have had the chance to go felt like a holiday. It was really special to be surrounded by that nature, and at the same time to know that we were making an impact for the species.  We actually found more new territories than they were expecting, and I feel very thankful to Noam, Inbar, and Eli for letting me be part of this.

Ana during a day off on Shlomo Mt, the Sinai peninsula in the background.

Ana during a day off on Shlomo Mt, the Sinai peninsula in the background.

The rest of March flew by, and the migration came to peak time. Steppe buzzards, black kites, black storks together with other species started to pack the skies. Days became longer, counting from sunrise to sunset. It was exciting and exhausting at the same time, but we were happy no matter how tired we were; having those numbers of raptors migrating in front of you gives the energy you need to keep clicking and counting. And that's what we did until the 10th of April when we completed the count.  From the 12th -14th of April we were part of the Raptor breeding survey, and we finished work the 15th.

After that I went traveling around the country, spending most of the time enjoying the north (Hermon mountain, Golan Heights, Hula Valley), and it was so different from the desert I had worked in. I returned to Spain at the end of April.  

Ana with Re'a in front of the Field House on her last day in Eilat. 

Ana with Re'a in front of the Field House on her last day in Eilat. 

It's difficult to summarize in a post a 3-month experience, so I hope at least I gave you a brief feeling of how it was. Not everything was just work, there were also days off, and I spent most of them going hiking in the Eilat mountains, where there was much to explore and see.

Israel is a beautiful country with very warm and welcoming people, and felt at home from the start. Thanks to everyone who made this experience so amazing for me: my teammates, all of the special people that stop by High Mt. station, Frank and his lovely company, Libi and Tdazok, but specially Noam and my good friend Re'a; without them none of this would have happened. 

Shalom!

For those who want to check the numbers of birds recorded this 2018 season, check this out: http://trektellen.org/search?q=Eilat

For anyone interested in migration, follow the Eilat Birding Center - IBRCE on Facebook!

On the Vulture Chronicles: Vulture Detectives Pt 2

A black vulture tagged by Hawk Mountain named Versace, perched on a barn in the Kempton Valley. Notice her wing tag and antennae of the telemetry unit.

A black vulture tagged by Hawk Mountain named Versace, perched on a barn in the Kempton Valley. Notice her wing tag and antennae of the telemetry unit.

By Adehl Schwaderer, former Conservation Science Trainee
Hawk Mountain Sanctuary

As a Hawk Mountain Conservation Science Trainee, you have the opportunity to be a part of many influential experiences, including counting migrants as they pass North Lookout and educating visitors about the importance of raptor conservation. But the experience that I have learned the most from this autumn was working with my fellow trainee Zoey Greenberg on our black vulture movement ecology project. This blog is part two of our vulture series so be sure to check out part one to gain a complete understanding of our project.

The plan was to locate three black vultures, Versace, Gifford, and Hillary, based on their recent GPS locations and observe what the birds were doing at these locations. To be honest, I wasn’t sure what to expect. I was excited to get started and gain new field experience, but no one had ever attempted groundtruthing with this species before, and it is still a new concept. We accepted this challenge with enthusiasm but were anxious about getting results. In the end we knew that no data would still be valuable information, however who doesn’t want groundbreaking results from their first ever field study?

....

Click here to continue reading this blog on The Vulture Chronicles

Click here to read Part 1!

On the Vulture Chronicles: Vulture Detectives Pt 1

Female black vulture named Donald over a quarry during September of 2016 near Palmyra, PA.

Female black vulture named Donald over a quarry during September of 2016 near Palmyra, PA.

By Zoey Greenberg, former Conservation Science Trainee
Hawk Mountain Sanctuary

he tires crunched on gravel, and I shut the engine off. We had entered vulture country. With scope, data sheets, and binoculars in hand my project partner, trainee Adehl Shwaderer and I walked carefully up the gravel road as we scanned the tree tops for hunched silhouettes or soaring shadows. This was our first foray into the Kempton Valley, east of Hawk Mountain, in search of black vultures (Coragyps atratus). Our expectations were not high. However, we had innovation on our side: we were testing a method called “groundtruthing” to better understand the movement ecology of several vultures that had been tagged with satellite transmitters by Hawk Mountain scientists. After investigating their movements in Google Earth, we had discovered interesting patterns including an individual who spent time near quarries, and another that seemed to prefer cities. The problem was, we didn’t know why.

...

Click here to continue reading this blog on The Vulture Chronicles

From Here, I Will Soar

Merlyn at Hawk Mountain's North Lookout

Merlyn at Hawk Mountain's North Lookout

By Merlyn Nomusa Nkomo, Spring 2017 Conservation Science Trainee
Hawk Mountain Sanctuary

I was born in the golden, warm and thorny savanna plains of Matabeleland in Zimbabwe; where the grass is soet veld (sweet fields/grassland) and elephants, kudus, impala are at home and the lion is their “king." The savanna is born of fire. Successive periods of fires resulted in this beautiful ecosystem from forest to open plains; she is golden as though purified by the fire and all the life from her is tough, resilient and rough around the edges. It is beautiful to watch her at dawn when the sun comes up over her while the birds sing, when the sun goes back to her at sunset, and her sky line becomes the towering giraffes and the acacias, and when the constellations above her smile on everything as it sleeps.

Pennsylvania is certainly the opposite of home, the beautiful mountains covered in dense forests of old tall hemlock and oak trees. The valleys have perennial rivers winding around the beautiful landscape as though every scene is from a painter’s brush. Hawk Mountain Sanctuary is nested in this beautiful state and is by far the best way to experience America for the first time if you are an African that loves the wilderness.

It is beautiful here, seeing the changes from just the view of your window and more so from lofty heights of North lookout as you sit on the humongous boulders and try to take it all in. Much has changed on the mountain since I first got here, and it truly has been to my joy and delight. The freezing snow I experienced for the very first time in my life when we arrived had engulfed everything in a blanket of white, even the surroundings of the mountain were in a cloud of fog and not much could be seen. However, as the days went by, the weather became more forgiving and the snow melted away. The grass was green and everything began to bloom. The sun came out and my shivers ceased and now, well now I cannot wait to go out in my shorts and hike.

I am an avid bird watcher and am so excited to be in the middle of a brand new world of birds here. Hiking was not really my thing, and, in my defense, the savannah is fairly flat grasslands, but if I have to hike up and down to see the birds here, I will.

As a bird lover, it has been such a joy, a dream come true even, to be around others like me, to talk all day about birds, oh what a joy! Others may not relate with this, but when you love raptors and birds the way I do and get the chance to talk about them in all kinds of conversations like whether it's serious talk (“sciencey talk”), casual talk, experiences talk, and even when you are making jokes, you are in bird lovers’ heaven with the saints.

I sit on the lookouts and face to the east, my mind tells me that far in the distant horizon past the ocean is my home, but my heart tells me this is my home away from home. This place so different from everything I know, but also so parallel to all that is familiar, so filled with opportunities to learn with each passing moment. This place, though not golden, is colourful beyond what I could ever have imagined. It’s ironic that one can find that his home, his place of utmost peace self discovery and growth, is a place that is the total opposite of what he/she has always identified with and has always called home. Hawk Mountain Sanctuary is that home away from home for me, and I am sure many like me have come here and felt the same; this is a special place, the school in the clouds as they call it. 

Red-spotted Newt photo taken by Merlyn

Red-spotted Newt photo taken by Merlyn

Hawk Mountain has been my place of a lot of firsts. This is so exciting for me, knowing every single day is certainly going to be different from the previous, knowing I will probably see or do something I haven’t done before. This is what being alive is. In any living thing, when growth ceases, decay begins; I am fortunate to have this experience and be conscious of it. I was in snow for the first time, shaking like a leaf but loving every moment of it. I saw and held salamanders, newts, and bears for the first time in my life, wildlife that you could never find in Sub-Saharan Africa. I also rode a bicycle for the first time since I was 5 years old on those bikes with side wheels.

It is definitely the place you go to and don’t stay the same; it is one of those very few places in the world where you can truly feel and see yourself change and grow. Hawk Mountain has certainly made me realise that I can be better than I was a day ago, that, if I work on it, whatever it can be, I can be better at it, that curiosity is good and asking questions, however silly you think they are is important for learning, and most importantly, listening to others from all over the world talk about their experiences, is a great way to learn about the world.

Who knew, in the 1930s when all those birds were being shot out of the air, that this small rural corner of America tucked away behind the mountains in dense forest would become the launching pad of hundreds like me? Young scientists who love conservation, some who have at some point second-guessed their abilities and felt hopeless when faced with the challenge of their local situations. Like Rosalie Edge and the Brouns' believed they could bring to an end the culture of shooting in their day, just by counting the hawks, I believe too that I can be part of the force that will stop the poisoning of vultures among other ills in Africa. 

Any challenge in conservation can be overcome, perceptions, attitudes, and wrongs people do can be changed, and it is up to us to be part of the force that brings the change.