My northward migration

It has been nearly a month now since I arrived in Alaska. I said my goodbyes to the Catalina field site on May 14th, caught a ride into town bright and early the following morning, and left the island for the first time in exactly three months. Talk about culture shock. The traffic and smog of LA and the hordes of unfamiliar people contrasted starkly with the small community where I had been living in the rugged interior of Catalina Island. But I survived. A shuttle quickly whisked me from the ferry terminal at Long Beach to the airport terminal at LAX, and soon I was onboard a flight bound for Seattle. The plane took off to the west and, in a fitting departure from California, it flew up the coastline in such a way that I had an excellent view of Catalina and most of the other Channel Islands (see photo of Anacapa and Santa Cruz). It was official: I was headed north, leaving behind our southern birds to catch up with their boreal-breeding counterparts.

My northward migration was of much shorter duration than would have been the case for the birds. I had a 3-hr flight to Seattle, a 3.5-hr flight to Anchorage, and a 1-hr flight to Fairbanks. In Anchorage I met up with Jongmin and Brent, who had arrived on separate flights, and was quickly reminded of my new location in the far north. Standing in the airport terminal not 5 meters from us was Jeff Corwin, a popular television personality from Animal Planet. We learned that he had just returned from a stint of collaring polar bears further north. I can only presume that his trip had something to do with the then days-old news that polar bears were being listed as a threatened species in the US. Regardless, there he stood in front of us. Not bad for a first impression of Alaska.

Our plane touched down in Fairbanks in the wee hours of the morning and there to meet us was Helen, who had arrived a few days earlier. She drove our dreary-selves back to the cabin where we were to stay, and there we crashed after our long day of traveling. We awoke the next morning and, after having skipped one day of fieldwork, I found myself strapping on my hiking boots and harnessing my binoculars around my neck. The first day was easy: we got a tour of the study plot, checked out some singing males, and paid a visit to an active bald eagle nest. The females were still on their migratory journey so that left us with time to settle in and adjust to our new surroundings.

But the calm period did not last long. Jongmin spotted our first female on May 18th, a bird carrying black, pink and orange leg bands that had been given to her the previous year. She took a few days to recuperate from her series of flights north and began building a nest on May 22nd. The females that arrived in the days and weeks to follow quickly followed suit, keeping us on our toes.

We have done well so far, with 29 nests and counting. The earliest are on the verge of hatching and the latest are still lacking a complete clutch of eggs. They are not easy to find. Orange-crowned warblers here nest exclusively on the ground, and the females are skittish if they notice us anywhere in the vicinity of their nests. It is therefore of the utmost importance to hide ones-self in the bushes to find the exact nest location for a building female, a feat of concentration when faced with a swarm of hungry mosquitoes.

We are now bracing for the upcoming nestling period when we will be running around video-taping nests and measuring nestlings, not to mention trying to find the nests we have missed. I will try to post in the weeks to follow but I cannot make any promises! In the meantime, I will leave you with this photo of a busy beaver and you can think of us.

North they go

It is that time of year again. Across the northern hemisphere the poleward procession of the snow-line is giving way to a swarm of migratory birds. We are reminded of that fact every time we see a bird, or hear a sound, that seems out of place. Migrants have been passing through Catalina since mid-April and have been doing so in waves. We had one such wave today, bringing with it Townsend's Warblers, Hermit Warblers, Black-throated Gray Warblers, Western Tanagers, and plenty of other species that I'm sure we missed. Over the years we have caught many of those migrants and, before releasing them unharmed, have had them pose for a few photos.

Hermit Warbler

Warbling Vireo

Townsend's Warbler

Wilson's Warbler

Orange-crowned Warbler

Ok, so I know what astute readers out there must be thinking: "Aren't you there studying a breeding population of orange-crowned warblers? Why is that last photo lumped in with the other migrants?" Well, believe it or not - on this same day last year - we caught a few orange-crowned warblers of the Alaskan/Canadian race that were migrating through Catalina (the above bird is smaller and has duller plumage than our local breeders). We don't know where those birds ended up, but they do serve to highlight just how delayed the northern breeders are. Here most orange-crowned warblers have raised a batch of young (i.e. a brood) by early May, but the Alaskan birds have just started to make their way north. In a few short weeks we will catch up with some of those birds in Fairbanks, and will start studying them just as their migratory journey ends and their breeding season begins. Until then, we will continue to enjoy the passing of migrants on Catalina Island.

To breed or not to breed?

Wow, it sure has been a while since I last posted to this blog! Sorry to anyone who was anxiously awaiting news of the warblers on Catalina Island. Assuming such a person exists, I can only imagine they had two options running through their head while pondering my post-less blog for the past two months: (1) the birds aren't breeding (again) and she has nothing to write about, or (2) the birds are breeding and she is just too darn busy. If you chose option number 2 - ding ding ding - you are correct. The birds did breed and we have a mountain of data to show for it.

We started the field season wondering when the birds would breed. Last year, after the driest winter on record, only a few of them did and we had to wait until mid-April to see that happen. But this year the island received a few inches of rain in the months that preceded our arrival, and some key storms in late February led to an immediate greening-up of our study site (see photo above). The oaks leafed-out and the birds quickly followed suit, building nests, laying eggs, and providing us with an actual breeding season as opposed to last year. Needless to say that made us happy, and busy at the same time!

I am used to migratory birds, where some birds arrive, you find their nests, and then other birds arrive, and you find their nests. But in this system the birds over-winter on the Channel Islands and the nearby mainland, so they had come to Catalina and had established territories weeks, if not months, in advance of the initiation of nesting activities. So when the environmental conditions were right, they all starting building nests at once! At one point it seemed like there were building females everywhere I looked.

The incredible synchrony that we observed this year was unusual compared to previous years, and created a situation that kept us on our toes for the next few weeks. We found most of our nests during the incubation period, either by following chipping females or by flushing them off their nests. This was a busy time, as we had many nests to find and only 4 of us on the ground trying to find them. Once we found a nest we had to carefully check it every 2 days to see if the eggs had hatched, and to monitor whether it was still or active or had been found by a nest predator.

On Catalina, there are quite a few nest predators in the form of snakes, foxes, mice, and other creatures. But the ones that seem most troublesome from the warblers' perspective are the snakes. For instance, so far this year we have positively identified two predators eating warbler young and both were of the reptilian variety - one a gopher snake and the other a california kingsnake. We started seeing snakes early this year. I spotted my first rattlesnake on March 9th (see photo) and proceeded to see many more in the ensuing weeks (one of which was far too close for comfort). This, after having gone an entire season without seeing a rattlesnake last year. Despite this, the birds had an exceptionally low rate of nest predation this year. Only a few of our nests were eaten in the month of March, and only in the past few weeks have predators been apt enough to find our warbler nests.

Lucky for the birds, and lucky for us. One of the things we are interested in is parental feeding behavior, and we study this by setting up a small pin-hole camera at nests and recording for an entire 24-hour period. But we can only do this if the nestlings survive long enough to be 6 days old. This year, many of them did and we were left running around video-taping nests and, on the following day, taking nestlings out briefly to weigh and measure them.

Through all this we had help from many people. In addition to Jongmin and myself, we had two field assistants actively searching and monitoring warbler nests. We were also fortunate to have our advisors - Drs. Cameron Ghalambor and Scott Sillett - visit in early March, a postdoc - Dr. Brent Horton - visit two times in March and April, and a labmate who is working on Santa Cruz Island - Helen Sofaer - visit in April. They helped to identify birds, to capture and band them, and of course to find their nests. It was truly a team effort.


So what are we up to now, you may ask? Well, believe it or not some of the birds are going a second round. They bred early, experienced an exceptionally high level of nest success, and still have the time (and food) needed to raise another batch of young. So they are giving it a shot at least. But it remains to be seen how successful this attempt will be. The predators seem to be picking up steam in terms of their nest-finding ability, so we are not expecting an incredibly synchronous (or busy) nestling period this time around. Stay tuned to find out!

Quirks of Catalina

Catalina is an odd place to work. This morning my alarm went off at 5:40AM and, after hitting snooze once or twice, I managed to sit up in bed and peer out my window. To my great surprise, there in front of me stood a large black silhouette. I rubbed by eyes and squinted out the window once again. It was still there, and as my eyes adjusted I came to realize that it was a bison. That’s right, a bison. An interesting awakening, to be sure.

So what was it doing there? Proximate answer: it was grazing. Ultimate answer: it descended from the herd of 14 bison that were brought to Catalina in 1924 for the filming of “The Vanishing American.” Since then, the herd has grown to a few hundred individuals and has become one of the most iconic symbols of the island. Tourists come to Catalina wanting to see bison, restaurants in Avalon sell “bison burgers,” and a bar in Two Harbors is known for a drink called “bison milk.” They garner more fame than the native species!

Bison run-ins are a frequent occurrence on our study plots. In fact, on our first day in the field Jongmin and I found 40 bison lingering around our parking area. Luckily they are terrified of trucks and are even scared of humans on foot, so they are easily displaced from areas where we want to work. They also make for an interesting sight, foraging on grasses in between patches of cacti. Not exactly what I would call typical bison habitat.

The bison story is but a part of the unique history that has shaped Catalina. It used to be a top vacation destination for the Hollywood elites. Back in the 1920s and 1930s, stars like Charlie Chaplan and Clark Gable made frequent appearances in the resort town of Avalon. The owner of the Chicago Cubs – Mr. Wrigley of Wrigley’s Gum – owned most of Catalina at the time, and the baseball team had spring training on the island. It was the happening place to be.

It was also a prime location for shooting movies. The island’s rugged coastline had the appearance of an exotic tropical island, and it was much cheaper to charter a boat from LA to Catalina than it was to travel all the way to an island, say, in the South Pacific. As a result, over 200 movies were filmed on the island in the early part of the 20th century. Each changed the character of Catalina somewhat, some with the planting of palm trees and others with the introduction of exotic animals like bison.

The Wrigley Family’s claim to Catalina Island lasted straight through to the 1970s, at which time they set aside 86% of the island for conservation and established the Catalina Island Conservancy to be a responsible steward of the land. Now, the island is less of a posh, celebrity-filled paradise, and is more of a sanctuary for the native flora and fauna that make this island truly unique. Indeed, if it hadn’t been for the generosity of the Wrigley Family, much of Catalina would have found its way into the hands of developers and would have a very different appearance than it does today. For that we are grateful, and are proud to report that Wrigley’s is our gum of choice as we meander through the cactus patches of Catalina Island, ever watchful for a lumbering bison.

Green grass and brown trees

A week has passed since our arrival on Catalina. Jongmin and I took the 1 hr long ferry ride from San Pedro to Avalon last Friday, taking advantage of the excellent weather and opting for the roof-top view of the surrounding ocean. The trip was much different than our last ride on the Catalina Express. This time, we were surrounded by tourists destined for Avalon at the start of the long weekend. Last time, we were surrounded by firefighters returning to the mainland after the so-called "Island Fire."

That was May 2007. The island was a parched landscape that had been suffering from the most severe drought on record, and 4,760 acres of the island's interior had just burned with the boundary extending right up to the city of Avalon. We were in the interior of the island for the duration of the fire, without power or contact with the outside world. Helicopters flew over our heads constantly as they made loops between the fire on the horizon and the reservoir in our backyard. The fire burned for a few days and when it was out we left the island, cutting short our field season by one week.

This year, upon our arrival in Avalon, we were pleased to find an island much greener than when we last saw it. There was grass, green grass, the oaks on the surrounding hillsides had grown new leaves and many of the flowers had started to appear. The island received several inches of rain in January and February and it showed. We were ecstatic. The breeding season would soon be upon us, or so we thought.

We retrieved our vehicle, left for us by the Catalina Island Conservancy, made a brief stop at the local grocery store, and set off on our journey into the island's interior. The drive took us through the Island Fire, the road still lined with eucalyptus trees but the surrounding oaks covered in fire-scars. Shortly thereafter we found ourselves in Middle Ranch and settled into what is called "the bunkhouse," a place we share with the Conservancy's field technicians.

The next morning we awoke before dawn for our first day of fieldwork. Our expectations heightened by the ever-present greenery, we were shocked when we drove into the canyon where our field site is located to find it looking even browner than when we left. The understory was a brilliant colour of green, but that stood in stark contrast to the canopy, which was an ugly colour of brown. The oaks had dropped their old leaves and most hadn't grown new ones. It was puzzling. How could they be so green on the rest of the island, and yet so brown on our study site?

Despite the rather sad looking trees, we were pleased to find many of our banded birds waiting for us on the same territories they held the previous year. Red-Aluminum-Red-Red, check. Aluminum-Blue-Orange-White, check. Aluminum-Red-Green-Red, check. We counted over 20 banded birds on the first day alone, and many more birds who have yet to be banded. The birds were back, but we had a sinking feeling that the breeding season would be weeks away. Few males seemed to have acquired females, and food didn't seem particularly abundant given the sparse foliage. Our continued surveys over the course of this week have only served to strengthen that suspicion - and so we wait.

Goodbye Colorado, Hello California

Winter is no more, at least for me - a rather odd thing for a Canadian to say in early February. The last snow to fall on my shoulders came last weekend when Jongmin and I were driving through Utah en route from Colorado to California. The snow quickly disappeared as we descended into Arizona, at around the same time that the conifers of the Rockies gave way to the palm trees of the southwest. Shortly thereafter we were in an even warmer California, our home for the next three months.

Our destination was not Catalina Island - rather, we made our way to Ventura, just north of LA, to attend the 7th California Island Symposium. The meeting took place from February 5th to the 7th and brought together folks who study pretty much anything on islands off the coast of California and Baja Mexico, from ecologists to geologists to archaeologists. There were representatives from universities across the United States and Mexico, numerous government agencies, and NGOs such as the Nature Conservancy and the Catalina Island Conservancy. Over 400 presentations shed light on ecosystems of the past and present, as well as management techniques and challenges specific to the region's many islands.

The sexy bird that it is, there were enough talks on orange-crowned warblers to fill much of the session on terrestrial birds, and yet another poster describing the project's work on Catalina Island:

Scott Sillett, "Annual survival of orange-crowned warblers breeding on Santa Catalina Island" (talk)

Helen Sofaer, "The effects of island scrub-jays on orange-crowned warbler reproductive behavior and nest success" (talk)

Jongmin Yoon, "Habitat modeling for orange-crowned warblers breeding on Santa Catalina Island" (talk)

Katie Langin, "To breed or not to breed? Demographic consequences of the driest winter on record for songbirds on Catalina and Santa Cruz Islands" (talk)

Hannah Montag, "Nest site selection in the Catalina Island orange-crowned warbler (Vermivora celata sordida)" (poster)

Hearing about research on the Channel Islands and seeing familiar faces has given us an extra spark of excitement as we head into the 2008 field season. On February 15th we will take the ferry from San Pedro to Catalina Island and commence our 5-month stint in the field. In the meantime, we are enjoying our final days of sleeping in past the crack of dawn.

The warbler with the orange crown

With a name that includes a bright colour like 'orange' and an ornamental description like 'crown', one might be under the impression that orange-crowned warblers are dazzling little creatures. That impression would be wrong. In fact, the orange crown is barely perceptible unless you see a male puffing up his crown in an aggressive display or you blow on his crown feathers while you hold him in your hand. Some have even gone so far as to label this little songbird the drabbest of all the warblers in North America.

Despite its lack of showy plumage, the orange-crowned warbler is a fascinating bird to study. It is one of the most widely distributed warblers in North America, able to inhabit conditions as diverse as the arid, Mediterranean climate of southern California and the sub-arctic, highly seasonal environment of Alaska and northern Canada. It also exhibits diverse migratory strategies. For instance, the subspecies we study in the southern portion of its breeding range is a year-round resident of southern California, while the northern subspecies migrates all the way to the Gulf coast to over-winter. Such differences in breeding locale and migratory strategy translate into marked differences in life history, as southern breeders have low fecundity and high survival while northern breeders have high fecundity and low survival. We ecologists classify these populations as falling at the 'slow' and 'fast' end of the life-history continuum, respectively, classifications that carry with them a whole suite of additional traits. Our primary research aim is to identify the causes and consequences of life-history diversification among populations of orange-crowned warblers.

So how do we do this? Well, 'unfortunately' this requires that nearly half our year be spent in the wilds of California and Alaska, a price we are willing to pay in the name of research. With our trusty field assistants in tow, we record the locations of territorial individuals, capture and band them for individual identification, and follow their breeding activities over the course of the season. We find nests, videotape them to observe parental activity, and when the nestlings are old enough we take them out for a brief period of time to band and measure them. The populations we study have non-overlapping breeding seasons, so we are able to spend February, March, and April in California and May, June, and July in Alaska. Stay tuned as our fieldwork gets underway and we to peer into the lives of these cryptic warblers.