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.

The bear necessities

Anyone who has been following my posts has probably figured out by now that I am essentially a scaredy-Cat.  I love being in the field, but when I’m there, I worry about anything and everything – from mountain lions all the way down to cows.  Unsurprisingly, bears have always featured pretty high on my list of worries.  Huge, powerful bodies, sharp teeth, and a distinct tendency to be irritable when surprised…what’s not to love?

My initial bear encounter took place during my very first field season, up the Queen’s University Biological Station – and, in fact, wasn’t an actual encounter at all.  I was working at the station as a field assistant, and my duties included daily inspections of approximately 200 tree swallow nest boxes.  One day, as I made my way through a grid of boxes, I suddenly realized that one was missing.  At first, I wondered if I was losing it: how could a nest box just vanish?  However, closer inspection revealed that the box was actually still there…in pieces on the ground.  The nest was torn apart, the nestlings were gone, and a pile of bear scat sat on the ground close to the wreckage.

Until that point, I had thought of QUBS as an entirely safe place to do fieldwork.  Finding the ruins of that box was a rude awakening.  I froze in place and stared frantically around the field, looking for other indications that a bear had been there – or, more problematically, was still there.

In the end, of course, I found nothing; the bear that had destroyed the box was long gone.  In fact, over the course of my two summers at QUBS, I never actually saw a bear, just heard occasional second- or third-hand stories of sightings.  I eventually accepted that I was highly unlikely to actually meet a bear at QUBS, and I relaxed.

All that changed when I started my PhD.  I was thrilled to be doing my fieldwork in the beautiful Okanagan Valley of British Columbia…but at the same time, my mind heard the word “mountains” and interpreted it as “bear country”.  And while no one would claim the Okanagan is overrun by bears, my research informed me that black bears are reasonably common there, and even grizzlies aren’t unheard of.  Too make matters worse, a lot of my work took place in vineyards, where bears can be a big problem in late summer, when they come down out of the hills to gorge themselves on the grapes.

In preparation for this ‘highly dangerous’ fieldwork, I purchased a plethora of bear bells (to warn bears people were coming) and a few cans of bear spray (to deal with bears that didn’t heed the warning).  Armed with these tools (and accompanied by a ceaseless jingling), I felt pretty secure wandering around my field sites.  That is, until one day, when a local asked me, “How do you tell the difference between black bear scat and grizzly bear scat?”

“I don’t know,” I said innocently.  “How do you tell the difference?”

“Well, black bear scat is full of berries.  And grizzly bear scat…well, it smells like pepper spray and jingles a bit when you kick it.”

With a wicked smile, he went on his way.  I stared foolishly after him, clutching my pepper spray while my backpack jingled faintly.

This conversation somewhat eroded my faith in my bear spray and bells.  On top of that, it turns out that ceaseless jingling is phenomenally annoying after a few days.  Add to that the fact that I kept accidentally leaving my bear spray behind in various locations (forcing me to spend additional time wandering around in bear country attempting to retrieve it) and it’s not hard to understand why I decided to abandon that approach.

But I was still not enthusiastic about encountering a surprised, irritable bear.  So I devised a new strategy: I would just talk to myself as I wandered the hills, providing fair warning to any bear in earshot.

However, I quickly found out that it’s hard to talk constantly when you don’t have anything in particular to say.  In desperation, I found myself thinking back to high school, trying to recall any lines of the poetry or prose we’d recited in English class.  As it turns out, the only thing I remembered was the prologue to Romeo and Juliet.  So day after day, I would stumble around the Okanagan back country, repeating “Two households both alike in dignity / In fair Verona where we lay our scene…” as loudly as possible.  It’s probably a good thing that I didn’t encounter too many people on my wanderings.  At least the bears of the Okanagan are now well educated.

I guess the star crossed lovers did the trick, because I didn’t actually see any bears for most of my first field season.  But one day in early August, as I was making my way back to the car in one of my most isolated field sites, I rounded a corner and found myself about a hundred feet from a black bear.

Given that I’d worried about this exact scenario all summer, I was surprisingly taken aback. I turned on my heel and started walking away briskly, trying not to look back over my shoulder.  Finally, though, I just had to know.  I whipped around to survey where the bear had been…only to realize it had vanished.  Now I had a new problem: there was definitely a bear in my immediate vicinity, but I no longer had any idea where it was, and it was a very long walk back to the car.

Isolated ranch field site in the Okanagan

Can you spot the bear in this picture?… Nope, I can’t either.

Clearly the thing to do was keep talking to avoid surprising it; unfortunately, though, Romeo and Juliet deserted me in my panic.  So I decided that the logical thing to do was call home and talk to my parents.

When I dialed my home number, my sister picked up.  I told her about the bear and explained that I just needed to stay on the phone to keep talking.  “That’s too bad,” she said impatiently.  “But I need to call my friend now.  Call Mum on her cell instead.”

Right.

I hung up with her, and did as she suggested, still striding in the direction of the car while swiveling my head vigilantly in all directions. This time, I managed to get a hold of my mum…and that’s when I learned that you never, ever, ever call your mother and tell her that you’re in the middle of nowhere, with an unseen but very real bear lurking around.  She was quite willing to stay on the phone with me, but had no problem letting me know that she was not thrilled with the situation overall.

Much to our mutual relief, I made it to the car with no problems, and I didn’t see another bear for the rest of the field season.  In fact, it was over a year before my next bear encounter.  This second run-in happened at a less isolated site, but played out in much the same way as the first.  I froze briefly, then did an about face and walked away.  And once again, after a few seconds, I couldn’t help glancing over my shoulder.  This time, the bear was still visible.  In fact, it looked an awful lot like he had also done an about face and was hurrying in the opposite direction as fast as his furry paws could take him.

Apparently some bears are aware that humans also have a distinct tendency to be irritable when surprised.

Red in tooth and claw

Hints of spring in eastern Ontario....

Hints of spring in eastern Ontario….

One crisp, clear March day a couple of years ago, I found myself driving out to the Queen’s University Biological Station with a friend.  She was going out to do fieldwork, and I was going out to help her (in an effort to pretend that I still did fieldwork).  It was a typical Ontario pre-spring day: the snowbanks along the roadside were almost as tall as the car, and the sun glinted off the drifts of snow in the fields.  However, there was also a faint warmth in the air, and the ice on many of the lakes and ponds was covered with a thin film of water and a fine webbing of cracks.

Just before we turned down the road leading to the field station, we passed a group of three deer standing somewhat forlornly in the snow along the edge of a large pond.  Anyone who has ever driven along a country road is well aware that deer tend to be flighty creatures, and these three were no exception.  As we passed them, they all jumped into action, taking the easiest route of escape – straight out onto the pond.

My friend brought the car to an abrupt halt, and we sat there, horrified, watching as their headlong flight was quickly reduced to a slipping, sliding walk.  Even in the car, we could hear the ominous creaks and cracks coming from the ice.  It was the same feeling you get driving past a car accident: we didn’t want to watch, but it was hard to look away.  We were sure it was only a matter of time until one of the deer fell through the ice and was unable to get back out – and there was absolutely nothing we could do about it.

 

This is one of the paradoxes of fieldwork: while the job naturally attracts people who want nothing more than to spend their days hugging trees and cuddling bunnies, doing the work often means standing aside and watching while a fox or a hawk rips the bunny apart.

I don’t think I’ll ever forget the first time I opened a nest box door to check on the family of five tree swallow nestlings inside – only to find a huge, satisfied-looking black rat snake curled up in the nest instead.  As I looked at him, I could see five bumps in his body, one for each nestling, and I had an (admittedly irrational) urge to grab him by the tail and shake him hard, until they all came flying out of his mouth.

Surprise! Not quite who I was expecting to find in this box...

Surprise! Not quite who I was expecting to find in this box…

Even worse was the first time I opened a box to reveal a nest full of dead nestlings.  This happens surprisingly often, when cold snaps in the early spring make food hard to come by, particularly for aerial insectivores like tree swallows.  In these stressful circumstances, parents may attempt to keep feeding the nestlings for a while, but at some point, most adults prioritize their own survival (or rather, future reproductive potential) and abandon the nest.  This also means that sometimes, you come across nests full of heartbreakingly cold, hungry, weak nestlings.  It’s hard to close the box and walk away, knowing that the next time you open it, they will all likely be dead.

Abandonment, predation, and death are not easy things to witness, and it can be tough to stand back and get out of nature’s way – especially if, like most field biologists, you’ve developed a certain amount of fondness for your study organism.  Sometimes, it’s tempting to do crazy things to try and fix the situation.  I’ve certainly screamed at more than my fair share of snakes, although it’s never bothered them much.  And the first time I came across a nest of dying birds, I begged my boss to let me adopt them.  (Which, incidentally, is not just against the law, but also virtually impossible to do, as simply keeping them adequately fed would be a full time job.)  Years later, when running my own field season in the Okanagan, it was my turn to explain to my field assistants why they couldn’t adopt the abandoned baby bluebirds.

Unfortunately, standing back and watching nature take its course is a necessary part of the job.  It’s often hard to resist the temptation to intervene – but if we do, we mess with the very thing we’re all out there to study: natural selection and survival of the fittest.  The parents of those abandoned baby birds will build another nest and give it another try when the weather turns warm again.  And, as much as the birder in me objects, the snake needs to eat too.  My job, when I’m out there, is only to observe – not interfere.

 

As for the deer we saw on the treacherous ice that day?  We sat watching them, on the edge of our seats, for at least two full minutes – afraid to keep driving in case we caused the sudden movement that made them fall through the ice.  (Full disclosure: not only was I worried about the deer, I was also very concerned that, if they did fall through the ice, my friend and I were going to have to jump in to the freezing water to try and help them – see previous point about doing crazy things.)

But in the end, the ice held and they made it safely to the opposite shore.  As they scrambled up the bank and disappeared into the forest, we couldn’t help but cheer for them.  As hard as it is sometimes to witness the cruel side of nature, that cruelty makes the small victories all the sweeter.

Unweaving the rainbow

Philosophy will clip an Angel’s wing

Conquer all mysteries by rule and line,

Empty the haunted air, and gnomèd mine—

Unweave a rainbow

(John Keats, “Lamia”)

When I first came across the Keats poem “Lamia”, I was a defiant science student sitting in a third year English class, fighting to prove to myself and to my somewhat sceptical professor that there was no reason a Biology major shouldn’t also do a minor in English Literature.

The poem immediately got my back up.  In it, Keats laments the rise of science, which he claims has robbed the world of its mysteries and made it predictable and boring.  Science will, he says, “unweave [the] rainbow” in a quest to understand it – and in doing so, destroy its magic.  No leprechauns and pots of gold for scientists; they’re all about wavelengths, prisms, and refraction.

Of course, when I read the poem as an undergraduate, I was full of enthusiasm for my chosen field and leapt to its defence.  It’s true that scientists conquer mysteries (if they’re lucky), I found myself arguing in class, but that doesn’t mean they take the joy out of the world.  Why should knowing how things work make them less interesting?

A bad day for Webster: Western bluebird male attacks Webster, my bluebird decoy.

“This is my box!”: bluebird attacking my decoy.

In fact, I thought – and still think today – that understanding the world, knowing what things are and how they work, makes life more interesting, not less.  For example, over the last decade or so, I’ve spent countless hours trying to catch birds, using a decoy and recorded birdsong to make individuals think their territory is being invaded.  And despite having done this hundreds of times, I still get a thrill when the territory owner reacts as science says he should, and comes in to defend his turf – every single time.

But I have a shameful admission to make: as I’ve continued in science, I’ve occasionally had the guilty thought that maybe Keats had a point.  The thing is, science can sometimes be really, really boring.  You can spend whole days weighing the smallest things (beans, bugs, fragments of bird claw) with a mind-numbing degree of precision.  You can spend so long staring up at the trees, looking for birds – or staring down at the ground, counting plants – that you develop a permanent crick in your neck.  You can enter data until your vision blurs, pipette until your wrist begs for mercy, and label samples until your fingers cramp.  It’s easy, while you’re wrapped up in the small, tedious, and sometimes mindless details, to miss the big picture.

And when you’re out in the field, the single-minded focus necessary to collect your data sometimes feels a bit like having blinkers on.  There may be beauty all around you – the view from your ‘office’ may be the most spectacular one imaginable – but there’s so much that has to get done, and so little time to do it.  Who has time to waste on stopping to smell the roses when it feels like your whole PhD depends on catching this bird or collecting that sample?

For example, people often assume that, because I work with birds, I must be an expert on them – the person to go to if you’re not sure what kind of bird you saw at your feeder last week.  These people are almost always disappointed.  In fact, I probably know less about birds than your average outdoor enthusiast, because when I’m out in the field collecting data, I divide them into only two categories: bluebirds (interesting; keep watching to gather data) and not-bluebirds (not interesting; forget about them or risk being distracted).  While this is kind of a sad way to look at the world, it’s also understandable. When you’re panicking about collecting every scrap of data you can in the little time available to you, it’s all too easy to forget to appreciate the mysteries, the haunted air, and the rainbow.

All this has been on my mind recently because I’m currently in the midst of completing perhaps the most joyless task a scientist can undertake: writing the Methods section of my PhD thesis.  Normally, I love to write – but every time I open this particular document, my heart sinks.  If there’s a way to make the meticulous detail of a scientific Methods section interesting, I haven’t found it yet.  Intellectually, I know that these details are important, because science is all about repeatability – but I can’t help but feel that focusing on them is sucking the magic out of what we do.  As I labour through lists of dates and times, equipment manufacturers and specifications, sample sizes and standard errors, I feel slightly sick that all my blood, sweat, and tears have been reduced to numbers on a page.

But when I sat down to write my blog post this week, I realized that that’s where stories come in.  To me, telling stories – like we do here at Dispatches from the Field – is a way of finding my way back to the magic that sometimes gets lost in the everyday routine of science.  The stories we tell here exist at the intersection of art and science: they provide context, let us focus on the big picture rather than individual elements, and allow us to capture parts of our experience that could never be conveyed in the minute detail of a Methods section.  Writing and sharing stories reminds me of the mystery and wonder in the work we all do.

I still think it’s incredibly satisfying to understand how the rainbow works – but I also see value and joy in using stories to weave it back together again once in a while.

IMG_0015

Revenge of the ruminants

When I first started doing fieldwork, I must admit that I spent a lot of time worrying about large mammals.  Even when I worked up at QUBS, in the relatively safety of eastern Ontario, I fretted about bears.  When I went to California, I obsessed about mountain lions.  And after working in Hawaii, I added feral pigs to my list of formidable and frightening creatures.

But until I began my PhD fieldwork in the Okanagan Valley, it would never have occurred to me to worry about cows.

I know what you’re thinking: how can cows be in the same league as bears or mountain lions?  After all, they’re vegetarians!  There is no chance that you’re ever going to be eaten by a hungry cow.  They just stare at you with their huge brown eyes and chew their cud meditatively.

Right.

As it turns out, you really don’t run into bears or mountain lions that often in the field.  (Not that I’m complaining.)  But what you do see – especially doing fieldwork in an agricultural area like the Okanagan Valley – is cows.  They’re everywhere.

This is especially true if your study species is partial to the type of habitat that often holds grazing cows.  When I was setting up my PhD field sites, I wanted to make sure to cover as many types of bluebird habitat as possible.  So while much of my research took place in vineyards or along walking trails, I also had two sites that were open rangeland.

The wide open spaces of one of my two rangeland sites.

The open spaces and sage brush of one of my two rangeland sites.

When I first set up nest boxes at these sites, I fell in love with the wide, empty spaces and the scent of sagebrush.  My rangeland sites instantly became my favourite.  But on my second visit to one of these sites, I got an inkling that they might be more problematic than I’d thought.  As the car rounded the last corner on the way to the site, I had to hit the brakes hard.  My field of vision was suddenly filled with milling brown and black bodies.  Cows, cows, and more cows…as far as the eye could see.

I pulled over to the side of the road and took out my phone to call the landowner.  He’d mentioned to me that they’d be bringing the cows in, but I had to assume they weren’t supposed to be blocking traffic.  “There must be a break in the fence,” I told him.  “The cows have gotten out and are all over the road.”

“Oh, that’s normal,” he replied.  “I’m sure the fence is fine.”

“But…” I started at the solid wall of bodies on the road in consternation. “…how did they get out, then?”

“Well, fences are more like…suggestions…to cows,” he responded.  “They usually ignore them.  But I’m sure if you honk at them enough, they’ll get out of your way.”

More trouble than they look...

More trouble than they look…   (Photo credit: Manisha Bhardwaj.)

From then on, the two rangeland sites were the bane of my existence.  No matter what was on my agenda when I arrived, the cows always seemed to be between me and where I needed to go.  It was like they had a copy of my schedule.  And it was never just one or two cows – wherever one went, the other 30 animals in the herd joined it, forming a dense, noisy, smelly barrier between me and my destination.

Also, as it turns out, cows and bird boxes are not a good combination.  The cows decided that the boxes were perfect scratching posts, and were irresistibly attracted to them.  Almost every time I arrived at the sites, one or more of the boxes would be hanging at a precarious angle – often with a perplexed bluebird sitting beside it.

And then, of course, there were the cow patties everywhere.

After a month or so, though, the cows and I had settled into an uneasy détente.  I was starting to think the situation was relatively under control – and that’s when the bulls showed up.

The first time I realized the cows had been joined by their male friends, I had just dropped my field assistant off at a site.  I happened to glance in the rearview mirror as I pulled away, only to see my assistant standing completely still about 100m away.  Straight across the field from her, staring her down, was a very large cow.  As it lowered its head and began pawing at the ground, it slowly dawned on me that it was really too big…and muscular…and horned…to be a cow.  As my field assistant ran for the car, I realized we had a problem.  From then on, we spent considerably less time at that site.

My other ranch site, on the other hand, remained blissfully free of bulls for most of the summer.  So while the cows and I continued to wage a cold war, I usually felt pretty safe.  By the time August rolled around, the fieldwork was slowing down and I had pretty much relaxed.

Then one day, I was out in the field with my assistant, banding a nest full of bluebird nestlings.  I had just taken two out of the box and was settling onto the ground with one in each hand, when I felt a malevolent gaze on the back of my neck.

I looked around in surprise…only to find myself making eye contact with a bull.  He was about 50m away, and though he appeared relatively unconcerned, there was no doubt that he was sizing me up.

I scrambled to my feet and started backing away, urging my field assistant to do the same.  We struggled cautiously up the small hill behind the box, turning frequently to watch the bull as he meandered closer to the box we’d abandoned. Every time we stopped moving, he would start towards us again – so we kept climbing.

As we reached the top of the hill, I realized two things simultaneously. One – we were out of hill to climb; if he kept coming, we were going to have to make a run for the car.  And two – I still had the nestlings I’d been intending to band clutched in my hand, peeping faintly.

Luckily, after 20 very tense minutes, the bull lost interest and headed on his way, allowing us to creep back down to the box and finish banding.  It took a little longer than that for my heart rate to come back to normal.

So, after more than a decade of fieldwork, here’s what I’ve learned: if you must worry, focus less on bears and the mountain lions, and more on the things you’re likely to actually run into.  And don’t let those big brown eyes fool you – cows are usually up to no good.

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Possible impossibilities

Over the last year, I’ve come to realize that one of the major downsides to writing up your thesis is sitting behind a desk for 16 hours a day – especially when you’re used to spending lots of your time outside.  So to remedy the situation, I’ve started taking every possible opportunity to sneak in a little fieldwork.  Early last spring, I decided to get my field fix by heading up to QUBS with a friend who needed to catch a few black-capped chickadees for her own thesis work.

It was a beautiful early March day – frigid, but bright and blustery.  Mounds of snow glittered in the dazzling sunlight, and the lake was still covered in ice.  We arrived at my friend’s study site, and set up the Potter trap (essentially a cage with trap doors over a feeding platform; when birds go for the food they trigger the doors and trap themselves), and backed off to await our first hapless victim.

Then we waited.  And waited.  And waited some more.

The woods, usually alive with movement and calls, had never seemed so silent. Even though I knew better, it seemed to me that there were no chickadees within 5 miles of our trap.  Sitting and waiting for something that seems increasingly unlikely to ever happen tends to cause your mind to wander.  As I sat there that day (getting progressively colder), I found myself thinking about all the time I’ve spent trying to catch birds over the years.

Ornithologists – indeed, all field biologists – frequently have to catch wild animals for research purposes.  However, although this is often the key step on which all subsequent steps depend, it is usually only briefly mentioned in the Methods section of scientific papers, glossing over all the effort, patience, and utter frustration involved in the process.  In reality, catching birds is a study in contradictions: simultaneously extremely stressful and extremely tedious.  This became particularly apparent to me during my first PhD field season in British Columbia.

I arrived in BC in early February, fired up with enthusiasm and determination.  My first goal was to find and catch as many wintering western bluebirds as possible.  On our first morning in the field, I dragged my field assistant out into the cold and snow, and headed for a place where (according to our sources) we’d be sure to see bluebirds.

Sure enough, we had only been walking along the trail for a few minutes when a small flock of the little thrushes appeared and settled into a nearby tree.  I threw down my bag and tugged out our net and poles, flinging supplies every which way in a frenzy to get set up and catch my first bird.

It seemed to take forever to get the net up.  We had to use a rubber mallet to pound the aluminum poles into the frozen ground.  Then we began to string the net between them.  But mist nets are delicate things, made of fine mesh to make them more difficult for birds to see.  They tangle easily and are quite difficult to handle with gloves; the more I hurried, the more complicated the tangles seemed to be.  So off came my gloves, thrown unceremoniously on the ground with the other discarded equipment, and I started untangling the net with my numb fingers.

Finally everything was in place, ready to go…at which point the little flock of bluebirds took off over the hill, leaving us sitting there in silence.

Having spent the effort getting the net up, I thought we might as well stay and see if the birds came back.  So we plopped down into the snow, staring at the empty net, blowing in the fierce wind.  The 6 by 4 foot stretch of mesh looked impossibly small in the big, wide world.  It seemed ludicrous to imagine that a bluebird would ever occupy that particular space – why would it, when there were so many other places it could be?

The wide open spaces of the Okanagan - and one lonely little mist net.

The wide open spaces of the Okanagan – and one lonely little mist net.

I was starting to get quite discouraged when suddenly soft chattering and whistles heralded the return of the bluebird flock.  I held my breath as they approached the general area of the net – and then let it out as they sailed straight over it to perch in a nearby tree.

Messing with my head: a male bluebird perches on the mist net.

Messing with my head: a male bluebird perches on the mist net.

The next thirty minutes felt a bit like being on a rollercoaster.  My hopes would go up, up, up as the flock fluttered their way towards the net…and then drop like a stone as they bypassed it.  (Or, in several extremely irritating cases, actually perched on the net itself.)

But then…it finally happened!  One of the males in the flock misjudged his trajectory, hit the mesh, and got tangled in its strands.  Despite my frozen and creaky muscles, I leapt to my feet, running full out towards the net.  But just as I stretched out my hand to grab him, he managed to free himself and took off into the nearby trees – quite literally slipping through my fingers.  (This happens more often than you might think.  In fact, just a few weeks later, a camera crew from a local station, filming us for a news story, witnessed a similar mishap.  They also recorded my frustrated response, which – if I’m going to be honest – involved a fair amount of profanity.  Luckily they edited the footage before it hit the news!)

We never did catch a bluebird that day…or the next…or the next.  In fact, although we put in roughly ten hours of effort a day, every day, for the next six weeks, we only managed to catch seven bluebirds in total. That works out to approximately 0.017 bluebirds per hour effort – a pretty high ratio of time spent sitting around to time actually spent handling a bird.  There were days when, as I stared at our little net blowing in the breeze, the idea of capturing a bird seemed absurd: a complete impossibility.

But then, every once in awhile, there would be a bird hanging in our net and the impossible would suddenly become possible.  And every time that happened, the feeling of triumph would make all the days of frustration worthwhile.  It’s amazing how good outsmarting a bird can make you feel!

The end result of all that work: putting a band on a bluebird.

The end result of all that work: putting a band on a bluebird.

The incredible journey

Even though it’s still August, and the air is hot and humid, I’m sure I’m not the only one who has noticed that the days are getting shorter, the nights are getting longer, and some of the leaves have a distinct reddish tinge to them.  We may prefer to pretend it’s not happening, but we all know it: fall is on the way.  For millions of birds across North America, it’s time to start thinking about packing their bags and turning their sights to the south.  As summer draws to a close and our forests and fields begin to empty out, I’d like to share a post about migration that I originally wrote for Land Lines, the Nature Conservancy of Canada’s blog, back in the spring – when all the birds were just returning.

“We’ve got rocks and trees, and trees and rocks, and rocks and trees, and trees and rocks, and…rocks and  trees, and trees and rocks, and water…in Canada.”

-Arrogant Worms, “Rocks and Trees”

Canada: land of rocks, tress, water...and endless highways.

Canada: land of rocks, trees, water…and endless highways.

Ever since getting my driver’s licence, I’d dreamed of driving across Canada.  As a concept, it seemed romantic and adventurous – the perfect way to really get to know my own country.  But the reality, it turned out, was a bit different.  As I set off from Sudbury on my second day of cross-country driving, I wanted to be excited.  The first day had been easy: only six hours in the car, and a friend waiting for me at the other end.  But today was the real start of the adventure.  Today, I’d be leaving the relative safety of roads I knew well and passing into territory that was unknown, at least to me.

As I pointed my car west and hit the gas, I was more terrified than excited. Six thousand kilometers is a lot of road – especially when you’re driving alone.  In an effort to kickstart my enthusiasm, I reached over to slide the “Canadiana” mix CD a friend had made for me into the car’s CD player.  As the first strains of the Arrogant Worms’ “Rocks and Trees” came over the speakers, I glanced out the window and couldn’t help but laugh.  A vast, lonely landscape met my gaze, composed of…well, rocks, trees, and water.  Somehow, the song wasn’t actually making me feel any better.

The purpose of this epic journey was to get myself out to BC, and begin my PhD research on the population of western bluebirds that breeds in BC’s Okanagan Valley.  Although there are bluebirds (of one species or another) across the country, I was particularly interested in this population because of their migratory behaviour: the western bluebirds in the Okanagan are partial migrants.  This means that while some birds migrate south in the fall, others hang around the Okanagan, gather into flocks, and brave the snow and cold of a Canadian winter.

Western bluebird flock (and one lone goldfinch) check out a heated bird bath on a cold winter day. Photo credit: Eva Durance.

Western bluebirds (and one lone goldfinch) check out a heated bird bath on a cold winter day. Photo credit: Eva Durance.

I’ve been fascinated by avian migration ever since taking my first Animal Behaviour course as an undergraduate.  This fascination has shaped the last eight years of my life, informing my research interests as a graduate student.  Migration is a common phenomenon:  every year, billions of individuals from more than 350 bird species across North America embark on migratory journeys.  Migration is ubiquitous, and each spring and fall, as I hear the honks of Canada geese passing overhead, I’m tempted to call it ordinary.  But this common phenomenon is composed of extraordinary feats.  As summer winds down in the northern hemisphere, birds like the 25g northern wheatear set off into the unknown, often travelling thousands of kilometers south to spend the winter in more hospitable climates.  In the case of the wheatear, individuals breeding in the Canadian Arctic and Alaska brave the perils of crossing the Atlantic, ultimately covering 14,000 km to reach their wintering grounds in sub-Saharan Africa.  Then, come spring, they do it all over again in reverse.

Migration captures the imagination of scientists and the public alike.  But what is it about these journeys that inspires and enchants us?  That’s a question I’d never been able to answer satisfactorily, but as I faced the vast, lonely distances of my own incredible journey, the answer became clearer: migration may be common, but it is also an extraordinary story of adventure and challenge.

It's just possible that I should have left earlier...

It’s just possible that I should have left earlier…

To begin with, you must decide when to leave.  For birds, timing of migration is affected by many things – from predator abundance to food availability and individual condition – but it’s crucial that they get it right.  This is especially true in the spring, when arriving too late on the breeding grounds can undermine the success of an individual’s breeding season.  However, timing is also important in the fall, when staying too late can mean encounters with the kind of weather you’d rather avoid – as I found out the hard way.

Of course, once you’ve decided to leave, it’s also very important to know where you’re going.  Unfortunately for me, I’m one of the most directionally challenged people imaginable.  (Despite the fact that driving from Ontario to BC essentially involves following the Trans-Canada highway west, a number of people were actually placing bets on whether I’d end up in BC or Nova Scotia.)  Luckily, I had help: before I embarked on my journey, my mother dragged me to the CAA to purchase a staggering number of maps.  I ended up with a separate map for every Canadian province west of Quebec, a very long set of driving directions, and a North American road atlas for good measure.  Despite this plethora of directional aids, I can’t deny making the occasional U-turn on quiet parts of the Trans-Canada.

Just in case you’ve misplaced your country: thank goodness for maps, directions, and road signs.

Just in case you’ve misplaced your country: thank goodness for maps, directions, and road signs.

Birds, of course, have to manage without the help of the CAA.  Instead, they get their directional cues from a variety of sources: the sun, the stars, and the Earth’s magnetic field.  Recent research also suggests that scent cues may play a role in guiding migrants to their destination.  In fact, despite decades of study, we’re still learning new things about how birds manage to navigate the vast distances involved in migration.

You can meet almost any need along the way, as long as you pick your stopping places carefully. If you find yourself suddenly in need of custom embroidery halfway across the continent, the World’s Largest Truckstop in Iowa is the place for you.

You can meet almost any need along the way, as long as you pick your stopping places carefully. If you find yourself suddenly in need of custom embroidery halfway across the country, consider taking a detour to the south: the World’s Largest Truckstop in Iowa is the place for you.

Now on your way, you face another problem: finding places to stop.  As I made my way across the country, I realized that Canada’s seemingly endless rocks, trees, and water didn’t make that challenge easy to overcome.  I quickly learned to appreciate the value of a good refueling point, preferably one with gas, clean washrooms, good coffee, and food packaged within the last decade.  As every migrant knows, finding ideal stops as you navigate an unfamiliar world is not easy.  You need to be able to quickly size up potential sites for their value.  If you decide to stop, you need to quickly figure out what to eat and how to avoid being eaten yourself.  For me, the most important part of finding stops was learning to compromise.  Under less than ideal circumstances, I decided, fresh food was optional.  Even clean washrooms could be optional – after all, all those trees have to be good for something.  Gas and good coffee, however, were non-negotiable.

Even when you finally reach your general destination, the challenges aren’t over.  It’s important to know exactly where and when to stop.  When I crossed the border from Alberta into BC, I cheered, pulled over, and took a victory photo.  Little did I know that finding my new home in the Okanagan would involve more U turns than the rest of my trip put together.  My directions said, “Follow the highway around a curve and the driveway will be on your left”.  Unfortunately, the highway in the Okanagan is nothing but curves.  I drove past my new accommodations three times before finally focusing on the right curve, noticing the driveway, and making the turn.  I don’t think I’ve ever been so happy to stop driving in my life.

During the course of my PhD, I made the drive to the Okanagan and back three times.  Each time, I took a different route, and each journey brought its own adventures, trials, and excitement.  Of course, I had it easy during my ‘migrations’: unlike me, birds travel under their own power, at the mercy of the unpredictable (and often nasty) elements.  But I still feel that my cross country travels gave me a unique opportunity to gain a more personal understanding of the ordinary, extraordinary phenomenon of migration.

Well worth the trip: the Okanagan Valley from above.

Well worth the trip: the Okanagan Valley from above.

There’s no place like home

“The bluebird carries the sky on his back.” – Henry David Thoreau

Western bluebird nestling peers out of nestbox.

Who’s there? Western bluebird nestling peers out of nest box.

It seems to be an immutable law of nature photography (at least in my experience) that anything mobile will move the second you’ve gotten your camera ready, leaving you standing forlornly with your lens pointed at empty space.

But on this particular summer morning, I seemed to be witnessing an exception to this law.  As two hikers scrabbled through their backpacks for cameras, a male western bluebird sat calmly on top of the nearby nest box, singing his heart out – completely unperturbed by his audience.

From my perch beside the hiking trail, I watched the hikers rifling through their bags somewhat frantically.  Although I’m very familiar with ‘perfect shot’ panic, in this case I was pretty sure the would-be photographers would have no trouble snapping their photo – since the bluebird in question was in fact my wooden decoy bird, Webster.  I had set him up on the box about 20 minutes earlier, hoping to lure in the bluebird that actually owned it.  Apparently neither hiker had noticed the clip attaching Webster to the box – or the speaker below, broadcasting bluebird song.

As the hikers finally pulled out their cameras, I thought about explaining the situation – but somehow it just seemed mean to spoil their excitement.  A few minutes later, as they continued on their way, their conversation floated back to me: “That was amazing!  I can’t believe he sat so still.  I love bluebirds; they’re so beautiful.  That just made my day!”

Webster, my decoy Western Bluebird, perches on the edge of a nest box.

Webster, my decoy Western Bluebird, perches on the edge of a nest box.

 

Everybody loves bluebirds.

One of the first things you learn as a science student is to be wary of making absolute statements.  When you say something is ‘always’ true, or the ‘the cause’ of something, you had better be able to back it up.

And yet, even though I am not willing to go out and interview the 7.2 billion people in the world to determine their opinion on bluebirds, I’m still comfortable making this statement: everybody loves bluebirds.  They are, in fact, inherently lovable – charismatic, highly visible little birds with beautifully vivid plumage, associated with happiness, spring, and the land somewhere over the rainbow.

All three bluebird species (eastern bluebird, left; mountain bluebird, centre; western bluebird, right) have beautifully vivid blue plumage.

All three bluebird species (eastern bluebird, left; mountain bluebird, centre; western bluebird, right) have vivid blue plumage.

I have to admit, when I decided to focus my PhD research on bluebirds, I didn’t realize just how much people love them.  I quickly discovered that there are both upsides and downsides to working with a group of birds so universally beloved.  To be honest, sometimes it made things considerably more complicated.  For one thing, it meant that people tended to be very interested in what I was doing.  While this is mostly a good thing, it can be difficult to focus on answering questions and doing fieldwork simultaneously.  For another, people were often very protective of ‘their’ birds, and reluctant to allow me to capture and band them – a totally understandable attitude, but one that sometimes made my work a bit harder.  All ornithologists are aware that banding is a stressful experience for a bird.  Although we try to mitigate that stress as much as possible, being ensnared by a net, grabbed by a giant hand, and then handled, poked, and measured…well, it just can’t be that much fun.  Ornithologists do what we do because being able to identify individual birds gives us important insights into behaviour and ecology that would otherwise be impossible.  Ultimately, banding birds may provide us with information that benefits the species (for example, by informing management plans) – but we are all very aware that no individual bird ever benefits from being banded.

But while public interest in bluebirds occasionally made my life a bit more difficult, there were also many upsides to working with such an iconic group of birds: chief among them, having a species to study at all.

Perhaps one of the main reasons that people love bluebirds is that they are, relatively speaking, easy to see.  They are dwellers of disturbed areas.  They love the long forest edges and wide open fields created by agriculture; unlike many other bird species, human-wrought habitat changes were largely beneficial for them.  However, in the late 1960s and early 1970s, naturalists began to notice a troubling trend: a persistent decline in bluebird populations.

Although bluebirds forage mainly in open areas, they build their nests within cavities in trees.  All three species of bluebird are secondary cavity nesters – meaning that, while they need cavities for nesting, they do not create those cavities themselves.   Instead, they depend on finding holes created and abandoned by other species of cavity nesters, such as woodpeckers.

So when bluebird numbers began to decline, people wondered if maybe there simply weren’t enough cavities for them to nest in anymore.  But if that was the problem, what had caused the decrease in available nesting cavities?  The answer was simple: while the actual number of cavities available was staying the same, the competition to use them was likely getting increasingly fierce – thanks mainly to the introduction of a number of invasive cavity nesting species, such as the European starling and the house sparrow, to North America.

Concerned citizens were determined to tackle the problem.  Getting rid of the advancing hordes of invasive cavity nesters was virtually impossible – so they approached the problem from the other direction, by building and installing artificial nest boxes.  These boxes were designed to exclude some of the larger competing species (such as starlings), and were carefully positioned away from sources of food for house sparrows, to decrease their interest in the boxes.

Putting up bluebird nest boxes in the southern Okanagan Valley of British Columbia

Putting up bluebird nest boxes in the southern Okanagan Valley of British Columbia

As public interest in the plight of the bluebirds grew, enthusiastic citizen scientists began to establish nest box trails across the continent – and populations of all three bluebird species began to rebound.  In 1978, scientist Lawrence Zeleny enlisted the help of the Audubon Society to found the North American Bluebird Society (NABS) – an organization which continues to actively promote the conservation of bluebirds and other cavity nesters today.

Currently, many populations of all three bluebird species are stable or increasing – thanks in large part to NABS and its network of citizen scientists.  Every spring, these citizen scientists maintain and monitor thousands of bluebird nest boxes across North America.  Volunteers like 91 year old Al Larsen (the subject of Bluebird Man, a recent documentary by wildlife filmmakers Wild Lens) spend many hours each year gathering detailed information on box usage and nesting success of bluebirds and the many other species of cavity nesters that use the boxes – ultimately producing huge amounts of data on a much larger scale than any single researcher ever could.

The bluebird recovery story is an inspiring tale of grassroots conservation success – a win for the birds, but also a win for the people who continue to put so much effort into protecting them.  Although I encountered a few challenges working with this ‘poster species’, I don’t regret for a second choosing to study bluebirds for my PhD.  Getting to know the bluebirder community gave me the opportunity to work with some of the kindest and most generous people I’ve ever met – people who went out of their way to help and support me.  Without them, my project would not have been a success.  But more than that, I found that I loved watching the bluebirds too. Even on the most frustrating field days, they made me smile – partly because of their charisma, but also because they are living proof that sometimes, we can make a difference.

Home sweet home

Home sweet home