How do you solve a problem like migration?

This post was initially published on the Science Borealis blog on April 27th, 2020. Check out their blog for more great science stories, published every Monday!

An ornithological pedicure: taking a claw clipping from a western bluebird for stable isotope analysis. Photo credit: Catherine Dale.

I can feel the rapid thrumming of the bluebird’s heart against my palm as I carefully manoeuvre its foot into position over a tiny Ziploc bag. I pick up my nail scissors and take a deep breath to steady my hand. I will only get one chance to make sure the miniscule claw clipping lands in the bag. If it doesn’t, I will have no chance of finding it…and no way to discover where this bird spent the winter.

Field biology often requires unusual skills. I have spent the last decade becoming an experienced bird pedicurist, because analyzing the chemical composition of tissues like claws and feathers is one method scientists use to determine the movements of migratory animals.

Unfortunately, this method suffers from the same drawback as many others: a lack of precision. As a result, many aspects of bird migration remain a mystery. But this spring, researchers at the Max Planck Institute of Animal Behaviour in Germany are entering the final testing phase of a new space-based tracking system, which they hope will revolutionize our understanding of animal movement.

The puzzle of migration

For Canadians across the country, the return of our migratory birds marks the beginning of spring. Each year, 2.6 billion birds cross the Canada-U.S. border, heading north to their breeding grounds.

Two thousand years ago, Aristotle believed the spring reappearance of barn swallows meant they were emerging from their winter hibernation at the bottom of ponds. Although we now understand more about animal migration, many questions remain – largely because it’s very difficult to track individual animals as they travel vast distances around the globe.

For many years, the only approach was to mark animals with bands or tags in the hopes of re-sighting them somewhere else. But the sheer number of animals that migrate makes seeing a marked individual again extremely unlikely.

A flock of shorebirds takes to the air at Oak/Plum Lake Important Bird Area, a migration stopover site in Manitoba. The mixed-species flock includes Wilson’s phalaropes, red-necked phalaropes, stilt sandpipers, pectoral sandpipers, dunlin, white-rumped sandpipers, and semipalmated sandpipers. Photo credit: Christian Artuso.

Putting the pieces together

In the 1990s, migration research took a leap forward when scientists realized the chemical composition of animal tissue reflected the place where it was grown. By analyzing the ratio of various isotopes in tissue (termed stable isotope analysis), researchers can roughly reconstruct an animal’s geographic history…which is why I found myself giving bluebird pedicures.

Scientists can also now track moving animals directly by fitting them with tags that record location. These tags can be divided into two broad categories. Archival tags, such as geolocators, record and store movement information. In order to find out where a tagged animal has been, researchers must recapture it and retrieve the tag.

Recapturing migratory animals often proves difficult, especially as many fail to return from migration. So when possible, researchers prefer to use tags that remotely transmit data to a receiver, eliminating the need to recover them.

But transmitting tags face a fundamental constraint: transmitting takes power, and the more power a tag requires, the larger it needs to be. Tags must weigh less than 5% of an animal’s body weight to avoid affecting its behaviour or survival. Considering that many migratory birds weigh less than 10 grams, making tags small enough for them to carry is a huge challenge.

A sanderling carrying a Motus nanotag. The tag’s long antenna is easily visible. Photo credit: Jessica Howell.

The amount of power required to transmit data depends largely on where the receivers are. Tags for ground-based tracking systems – with receivers located on the Earth’s surface – can be very small. For example, the nanotags used by the Motus Wildlife Tracking System range from 0.2 to 2.6 grams, and can even be carried by some large insects. However, the range over which ground-based systems can track individuals is limited. Animals carrying Motus tags can only be detected within approximately 15 km of a receiver.

In contrast, satellite tags send data to receivers on orbiting satellites. They can track movement at a much larger scale than ground-based systems, and have been used for years on big animals, such as seabirds and caribou. But most satellite tags are too heavy for small migratory birds.

The Icarus Initiative

In 2007, Martin Wikelski, the Director of the Max Planck Institute of Animal Behaviour in Germany, proposed a novel space-based system for tracking animals across the globe.

It took more than 10 years, and the cooperation of the Russian Space Agency (Roskosmos) and the German Aerospace Centre (DLR), for the system to become a reality. In March 2020, the International Cooperation for Animal Research Using Space (Icarus) entered its final testing phase. The first Icarus tags are waiting to be shipped to researchers, and the system will be available to the scientific community this fall.

“We wanted to build [a tracking system] specifically for wildlife,” Wikelski says of Icarus. “It’s built by the community, for the community.”

The International Space Station, pictured here in 2009 after a visit by the space shuttle Discovery to add additional solar panels. Photo credit: STS-119 Shuttle Crew and NASA.

Icarus tackles the trade-off between tag size and transmission distance in part by the simple expedient of moving the receiver closer. Conventional satellite tags transmit their data to Argos satellites, which orbit the poles at an altitude of 850 km. Icarus tags will transmit their data to a receiver on the International Space Station (ISS), orbiting at an average altitude of 400 km.

Data collected by Icarus will be stored in Movebank, a free online database accessible by the public.  The system will also incorporate a citizen science initiative: Animal Tracker. While Icarus tags tell scientists where an animal is, citizen scientists can provide information about what it’s doing there. Using the Animal Tracker app, people can follow tagged animals online, and anyone who spots those animals in the wild can submit their observations to the database.

Of course, like any tracking system, Icarus will have some limitations, at least initially. The first tags will weigh five grams, which – while smaller than many satellite tags – is still too heavy for most migratory birds. However, the design of a new generation of tags weighing only one gram is already underway.

Satellite coverage will also be an issue. The receiver on the ISS will be able to pick up signals from most of the Earth’s surface; however, high latitude regions in the north and south will not be covered. Eventually, Wikelski’s goal is to deploy dedicated Icarus satellites strategically to cover the entire globe.

But even with these limitations, scientists are eager to begin harnessing the power of Icarus to tackle some of the unsolved mysteries of migration. Dr. Kevin Fraser, an Assistant Professor in the Department of Biological Sciences at the University of Manitoba, is keenly awaiting his first shipment of tags. He and his graduate students plan to put them on saw-whet owls – and they are most interested in the birds that don’t come back in the spring.

Banding a saw-whet owl. Kevin Fraser’s lab hopes to use Icarus tags to track these small owls during migration. Photo credit: Kevin Fraser.

Fraser’s previous research has largely depended on archival tags, meaning tagged birds must be recaptured to determine where they went. Individuals that don’t return to the study sites to breed – those that die along the way, or the young birds that disperse to breed elsewhere – are lost data.

“Most of what we know about migration, we know from birds that have successfully migrated,” Fraser says. “We know much less about where survival might be limited, or what the juveniles are doing. But [with Icarus], for the first time, we will be able to track 100 gram birds (the smallest yet) in near real-time, without the bias of only focusing on survivors and adults.”

Solving the puzzle

With the sliver of claw safely stowed in a bag for later analysis, I’m ready to liberate my captive bluebird. I position its feet over my empty hand and release my hold. For a moment, it perches on my palm, apparently unaware of its freedom…then, in a flutter of wings, it’s gone.

Of the 450 bird species found in Canada, 78% spend at least part of the year outside our borders. This fall, four billion birds will cross our southern border to spend the winter in warmer climes. More than a billion of them will not return, succumbing to the dangers of the journey or the hazards of their wintering grounds.

Icarus offers us a unique window into the world of migratory birds, and a chance to improve their odds. If we know where they go and how they get there, we can begin to understand the perils they face – and perhaps develop solutions.

Whiskers, photos and polar bears, oh my!

We are excited to welcome our first guest blogger of the new decade, Paige Bissonnette, a master’s student from University of Manitoba. Today Paige tells us all about her fascinating work with polar bears! For more about Paige, see the end of this post. 

As our tundra vehicle rolled into the docking station, an armed bear guard escorted us to our bus to be shuttled back to the Churchill Northern Studies Centre. I had just spent the day observing polar bears and being called a researcher by 30 tourists. Just like the guests on the tundra vehicle, I too was grinning from ear to ear, brimming with excitement.

My excitement had been building, slowly, ever since 4th grade, when a researcher came to my class and taught us about climate change and species-at-risk. The poster child for the talk was, you guessed it, the polar bear. After the talk, I was so excited about polar bears that I spent all my time in the library trying to learn more about them and threats to their habitat – even going so far as to cite my sources in my notes.

Fourteen years later, I had become the expert answering eager questions from groups of enthusiastic tourists. When I was given the assignment to co-lead learning vacations in Churchill, I was one part excited and 99 parts nervous. How did I get this job? Was I qualified to answer questions? Imposter syndrome was running rampant, as I’m sure it does for most graduate students at the beginning of their careers. I could easily relate to the tourists’ excitement: my dream was to see a polar bear in the wild, and here I was snapping photos through a tundra vehicle window.

But the goal of my trip was greater than capturing an Instagram-worthy photo. While I was primarily here to collect data for my master’s research on polar bear behaviour, my job also included using my knowledge, passion, and curiosity to encourage visitors to become citizen scientists, and contribute data to an ongoing long-term research project.

As the ice on Hudson Bay breaks up each spring, polar bears are forced onto the shore, away from their primary prey of ringed seals. While on land, they enter a fasting period, relying on a thick layer of blubber to support the energetic demands of maintaining their body temperature in the harsh Arctic environment. Pregnant females head upland, away from the shore, to build dens to birth their young. Non-pregnant females and males will spend time on land, resting and waiting for the ice to form in the fall. This is the most opportune time to see polar bears in the wild, and tourists and wildlife photographers flock to Churchill, Manitoba, “The Polar Bear Capital of the World”, to view the bears in their natural environment.

Thousands of photos are taken each year on these trips, and scientists realized there might be a way to use these photos to learn more about polar bear populations. In 1994, researchers developed a method to non-invasively identify individual polar bears through their whisker spot pattern. Each bear has a unique pattern of hair follicles, a whiskerprint (similar to a human fingerprint), that can be deciphered by a computer program. This discovery was the start of a long-term research project on the Western Hudson Bay population of polar bears. Photos taken by tourists, aka citizen scientists, are now fed into the whiskerprint program and used to estimate the size of the polar bear population in the area east of Churchill, and determine which bears are coming back year after year.

A curious polar bear checking out a tundra vehicle window.

In 2017 and 2018, as a graduate student at University of Manitoba, I went up to Churchill to collect data for my thesis, continue the citizen science project, and communicate findings from this project to the tourists who came to see the bears. Each day, we headed out into the field on a tundra vehicle which seated around thirty people. The journey into the middle of the tundra was roughly an hour of travel across uneven terrain and over frozen streams, as anticipation built among the tourists. Finally, someone would yell out, “I see one!”, and guests would rush to their window, binoculars in hand, to gaze out the window at a polar bear kilometers away. The tundra vehicle would screech to a halt and we would sit and wait to see if the bear was interested enough to come closer to us. Often, after a patient and silent wait, it would amble in our direction. Amid gasps of excitement and shuffling to the window with the best view, we would try to ensure we got photos of each side of its face. Guests often brought me their cameras, enthusiastically asking, “Is this one good? How did I do?” They began to gain a sense of purpose – gathering not just their own collection of cute photos, but data for wildlife research as well.

While in the field we took opportunities to gather as much observational data as possible, not only for our research, but to also to show the guests how much information can be collected non-invasively. Guests often shouted out, “the neck is larger than the head; the guard hairs are long – it must be a male”; repeating little bits of information we had discussed earlier. We also discussed how a changing climate has resulted in a decline in body condition for most bears. To measure body condition non-invasively, we took full body photos of the bear. I explained that we would measure the number of pixels from the top of the shoulder to the bottom of the foot, and the top of the back to the bottom of the belly to create a ratio of body proportion, similar to the measure of body mass index that uses weight and height. The guests were eager to help me take body condition shots, and aid in data collection.

I had a personal stake in the photos, as I am studying whether body condition influences social interactions between polar bears, specifically play behaviour. Adult mammals rarely play; they allocate most of their energy and time budgets to competition, feeding and mating. When social play does occur, it’s usually during periods of plentiful resources, when animals have extra time and energy to spend on seemingly purposeless activities such as play. However, in the western Hudson Bay region, adult male polar bears have been spotted engaging in social play. Polar bear social play consists of wrestling or sparring; males will rear up on their hind legs and wrestle, using moves similar to those used when competing for mates or resources.

We can’t ask the bears why they are playing during a resource limited time when they should be conserving energy, but we can determine what affects the duration and occurrence of social play. The body condition photos taken by guests on the learning vacation to determine if bears in better body condition play for longer or tend to initiate play.

Male polar bears sparring 100m away from our tundra vehicle

Each day, after collecting data out on the tundra, we returned to the research station, organized hundreds of photos, and began to analyze them. I walked the guests through the whiskerprint program, showing them how we extract a print and compare it against photos in our dataset to determine the bear’s identity. I could feel that the guests had a new-found sense of belonging to the scientific community. They were contributing to a long-term data set and coming to the realization that science is for everyone – not just graduate students and professors. Working with the guests on this project also brought me a sense of joy – as I felt I had come full circle. When I set out on this adventure, I had no idea what science communication meant, or the impact it could have. Now here I was, sparking curiosity in members of the public, just like the speaker in my 4th grade class.

I also felt proud that in addition to answering questions about polar bears, my research was helping teach people about the scientific method, making them into citizen scientists. Citizen science is a powerful tool that has helped catalyze innovative research techniques and allowed for the collection of much more data than individual scientists working alone would be able to assemble. Including the public in the data collection and analysis process improves scientific literacy and makes people feel included in the scientific community. Tapping into the public’s natural curiosity about the world allows scientists to answer questions that would have been impossible to answer alone, and more importantly, helps create a sense of care about the issues wildlife and the environment face.

A mom and two cubs keeping warm in a polar bear pile up.

Paige Bissonnette is a master’s student at University of Manitoba studying polar bear social behaviour. She focuses on using non-invasive techniques and novel technological approaches to assess the factors that influence polar bear social play. She is passionate about sharing her love of polar bears and the Arctic through science communication initiatives.

Technology in Fieldwork: Friend or Foe?

When I started doing fieldwork about 12 years ago, I didn’t use technology in the field. In fact, the only technology I had access to was an old flip phone that took photos so blurry I could barely tell if they were of plants or animals when I got back to the lab. I didn’t even pre-print my Excel data sheets and fill them in as I collected data. I just drew freehand columns in a Rite-in-the-Rain notebook and then spent hours afterwards trying to decipher my messy handwriting.

But over the last decade, technology has really boomed and it has changed the lives of field biologists everywhere. Take GPS, for instance. While hand-held GPS devices were certainly around 10 years ago, they tended to be clunky and slow, with limited functions – nowhere near as streamlined as current technology. In fact, they were often more trouble than they were worth. When I used to monitor roadside populations of wildflowers throughout the summer, I would simply remember where locations were based on landmarks, nearby street addresses, etc.

But now, I do my fieldwork using Collector, an mobile data collection app which allows me to take points instantly from my smartphone. If I were monitoring roadside wildflower populations now, I could just drop a point for a population, take a photo and attach it to the point and then navigate directly back to the point on follow up visits.
While GPS advances are very cool, the advent of iNaturalist is likely responsible for the greatest change to my life as a field biologist. According to their website, iNaturalist “is a lot of different things, but at its core, [it’s] an online social network of people sharing biodiversity information to help each other learn about nature. It’s also a crowdsourced species identification system and an organism occurrence recording tool. You can use it to record your own observations, get help with identifications, collaborate with others to collect this kind of information for a common purpose, or access the observational data collected by iNaturalist users” iNaturalist.

That explanation is much more eloquent than my description of iNaturalist, which can be summed up as, “a crazy-cool identification app that must be magic!”
When I was learning how to identify plants during my Undergraduate degree, I didn’t have access to anything like iNaturalist. To figure out what something was, I would excitedly bust out my plant bible, Newcomb’s Guide to Wildflowers, and open the book to the first page. Then I would carefully examine the features of the plant I was trying to ID. I would check if the leaves were alternate or opposite, determine whether the leaf edges were serrated, and then classify the radial symmetry of the flower. This information would lead me to a page number; with great anticipation I would flip to that page and quickly scan the images and descriptions. Inevitably, one of two reactions would follow: heart-beating excitement when my eyes stopped at a sketch that looked just like the flower in front of me…or sheer disappointment when nothing matched. In the second case, the next step was to flip back to the first page and take another look at the plant in front of me to try to figure out where I went wrong. Perhaps I miscounted the petals, or maybe the leaves were whorled, rather than opposite? It sometimes took a whole lot of trial and error, but eventually I almost always arrived at the right answer. And it was those mistakes that really made me remember the identity of the plant long after.

It is with some hesitation that I admit this, but I mostly use iNaturalist to identify things now. I just snap a photo of something in nature – be it a plant, an animal or a fungus – and iNaturalist gives me its best guess at the identity. It only takes a couple of seconds and it’s incredibly accurate. (Hence, magic app!) iNaturalist is such an exciting concept. In fact, I recently was part of a class visit at a Nature Reserve which involved a scavenger hunt as part of the tour. One of the species the students needed to find was Sensitive Fern, but this species is only really found in one small area, so it was easily missed by the students. To help them out, I pulled out my phone. I pointed to a specimen on the ground beside me and took a photo. Below is what iNaturalist came up with:


We proceeded to try the app on about a dozen more species of plants (even just the bark of trees!) and it was bang on every time. The entire grade 7 class was hooked on the app after that.

I love iNaturalist and all that it stands for. It intrigues people, it helps them learn about nature, and it fosters a curiosity about the natural world around us. It even helps collect important data about rare species and Species-at-Risk that monitoring biologists may miss. However, even though iNaturalist is useful in so many ways, it left me feeling very conflicted.

I can’t deny that iNaturalist has also made me a less engaged (or maybe a lazier) field biologist. To be clear, I don’t mean I am worse at my job now, by any means. In fact, I am probably more efficient. That being said, I don’t notice the things I used to notice about plants. I snap a photo and the answer is right in front of my eyes. I don’t spend 5 minutes flipping through the pages of field guides attempting to identify an unknown specimen. Moreover, when I do use iNaturalist, I often quickly forget the identity of the species – because I haven’t spent those long minutes working for my answer.
So, as I wind down this field season and think forward, I vow to reach for the book and not the phone next spring when I spot a new species or can’t recall what something is.

That being said, I think there is certainly a place for both technology and more traditional approaches as well. For those getting started, or in time sensitive situations, perhaps iNaturalist is the way to go. But maybe for those looking to thoroughly and deeply understand nature, the old school approach may be more suitable. Either way, I will continue to promote iNaturalist like the “crazy-cool magical app” it is, in hopes that more folks learn about, and begin to care about the natural world around us.

Do you use technology to do your fieldwork? Has the role of technology changed over the past few years? I would love to hear about your experiences! Leave a comment below and tell me – is technology a friend or a foe in your fieldwork?