Fur, Not Feathers

Caribou is our most abundant mammal in the study area once the herds arrive. This caribou calf, or "baby 'bou" as we like to call them, was born earlier this summer, and is taking a brief rest while his mother grazes nearby.

Caribou is our most abundant mammal in the study area once the herds arrive. This caribou calf, or “baby ‘bou” as we like to call them, was born earlier this summer and is taking a brief rest while his mother grazes nearby.

 

As is to be expected, these posts generally revolve around birds.

However, it would be foolish to leave mammals out of the picture, as they are an integral part of the lives of birds and our own lives. Here on the tundra there are five species of mammals that we regularly see (not including humans): caribou, Arctic Fox, Arctic Ground-Squirrel, Greenland Collared Lemming, and Brown Lemming. Occasionally we encounter a Gray Wolf or a Brown (Grizzly) Bear. Our team has dreams of encountering a Wolverine someday, which has become a common discussion at our campsite. If we hike the three miles to the edge of the Arctic Ocean, there are usually at least a few Ringed Seals around, and perhaps a Beluga Whale or a Narwhal if you spend enough time watching.

Caribou, the mammal we see most frequently each year, seem to live highly unenjoyable lives. In their annual migrations they spend the winter in the Arctic, migrate thousands of miles while being hunted by bears, wolves, and sometimes people, and then spend the summer trying to escape death by insects.

Mosquito levels affect the arrival dates and total number of caribou that come through the Canning River area.  Since the insects come out when the temperatures rise, in a warm year the caribou come back earlier (about 20-25 June), and in a cooler year they come back later (about 25 June-5 July). The caribou numbers increase on the coast in warmer weather since coastal regions are generally cooler and windier and offer caribou a break from the winged insect hordes that haunt them as they trudge across the tundra.

These insects, especially mosquitoes, have such an effect on the caribou that the drop in blood pressure from blood loss to insects can potentially result in death – a process known as exsanguination. We usually encounter groups from the Central Arctic caribou herd, in numbers that vary annually between about 5,000 (this year), to 30,000+ (2013).  When caribou numbers are high they can have a massive effect on shorebirds as they can trample nests by random chance when they move through the study area. We lost at least 6-8 nests this year due to caribou trampling.

Part of a herd of ~1,800 animals, this Caribou came within 15 meters of me as it headed toward the coast in an attempt to escape the cloud of mosquitoes and other biting insects.

Part of a herd of about 1,800 animals, this caribou came within 15 meters of me as it headed toward the coast in an attempt to escape the cloud of mosquitoes and other biting insects.

 

When the caribou arrive, so do the large predators. This year we have seen two Brown Bears in the study area, but we haven’t seen any wolves yet. The number of predators we see is also variable and is tied to how many caribou we see. It is not a surprise that we have not encountered any wolves, since we have only seen a few thousand caribou. Last year we did not see any wolves, but we found wolf tracks 200 meters from our sleep tents, indicating that one that silently trotted by in the middle of the “night”, unfortunately unseen. In 2012 some members of this camp watched a small group of wolves take down a caribou a couple of miles away from camp, followed by a Brown Bear that chased the wolves off of the carcass to take a turn.

The two ends of the Caribou spectrum - an older male with an impressive set of antlers towering over a calf born this year as the herd marches onward.

The two ends of the caribou spectrum: an older male with an impressive set of antlers towering over a calf born this year as the herd marches onward.

 

Arctic Foxes are the primary predator here on everything but the caribou, and we see them almost every day.

Slightly larger than a house cat, these small canines spend their days bounding around the tundra in search of lemmings and shorebird nests. We researchers share the foxes’ goal of locating shorebird nests, but unfortunately once the shorebird nest is located our goals diverge. We want to monitor the birds and the foxes want to eat them. As a result, we don’t always enjoy the presence of the foxes as much as we should, especially in years like 2012, when over 80% of the nests fell victim to predation, almost entirely due to an active fox population.

No matter how unfortunate it might seem to us, the foxes are an integral part of the arctic ecosystem, and not having them would paint an entirely inaccurate picture of the breeding success of the shorebirds that we study. Some years there are active fox dens, which ramps up the food needs of the adult foxes to provide for their large litters of fox kits. This year we have a den right near camp that had at least eight kits at one point. We have watched the adults make food runs back and forth with mouthfuls of lemmings and occasional shorebird chicks, attempting to sate the voracious appetite of a young fox.

One of the kits from the local Arctic Fox den was quite curious to see humans, clambering around in the open with a few of its litter-mates.

One of the kits from the local Arctic Fox den was quite curious to see humans, clambering around in the open with a few of its litter-mates.

 

Arctic Ground-Squirrels live in all the higher bluffs and small ridges that stand about 30 feet above the surrounding tundra. Since we live on one of these bluffs, we have 3-4 resident ground-squirrels that reside near our tents. One of them is exceedingly bold and will often venture right into camp, poking around in our bucket of dirty dishes in an attempt to find a tasty morsel. Luckily, we keep our camp clean. In fact, while I was typing this post in the main cook tent, our bold squirrel friend came right into the tent, less than a foot away. When they’re not nosing around, the ground-squirrels usually stand at attention by their tunnels (think prairie dogs), giving alarm calls whenever a fox or jaeger gets too close for comfort.

The diets of ground-squirrels are quite broad, consisting of everything from shorebird eggs and lemmings to flowers and tender grass shoots. The zones around some of the squirrel tunnels are devoid of certain species of flower that they especially seem to enjoy.

The diets of ground-squirrels are quite broad, consisting of everything from shorebird eggs and lemmings to flowers and tender grass shoots. The zones around some of the squirrel tunnels are devoid of certain species of flowers that they seem to especially enjoy.

 

The last of our regularly encountered mammals, our two species of lemmings, are also the smallest. Lemming numbers follow an annual cycle, where they will increase in abundance until reaching a peak year, upon which the population crashes to a small size before beginning the cycle all over again. This year was a good year for lemming sightings (the reason for the abundance of avian predators was talked about in a prior blog post), and both the Brown Lemming and Greenland Collared Lemming have been seen most days during the field season. Lemmings live all winter long under the snow pack up here, eking out an existence in little spherical nests they make out of grass and stock with food in the fall.

The number of lemmings in any given year has a strong effect on shorebird success in that year and the couple of years following because of their role in the diets of the Arctic Foxes. In years when lemmings are abundant, the foxes will focus more on hunting for lemmings. This spares more shorebird nests and results in higher shorebird breeding productivity.

If there are enough lemmings, like this year, the foxes will breed. This means that no matter how many lemmings are around in the next couple of years, the injection of more foxes into the local ecosystem will have a negative impact on shorebird nest success for at least the next year or two.

The adult Arctic Foxes seemingly never rest, constantly on the move looking for something to eat or delivering food to their kits. This adult was seen heading back towards the den with two lemmings - one Greenland Collared Lemming and one Brown Lemming.

The adult Arctic Foxes never seem to rest, constantly on the move looking for something to eat or delivering food to their kits. This adult was seen heading back toward its den with two lemmings  - one Greenland Collared Lemming and one Brown Lemming.

 

The most amazing thing about all of the species up here is how they are so intertwined in this ecosystem. The number of mosquitoes affects the presence of caribou and the amount of food available for shorebird chicks. Whether there are lemmings around in high numbers determines how many avian predators there are, whether foxes eat more shorebird nests, and if foxes will be more numerous in future years. In the three summers that I have been fortunate enough to spend at the Canning, I have been struck by how no two years are the same. You can miss much of the larger picture by simply spending one field season in a location, thinking you understand the deeper processes of the area when you are really only scratching the surface of the mysteries of the tundra.

 

 

 

Hatching Time

Adding to the appeal of a fluffy newly hatched shorebird, they hatch with disproportionately large legs. These Pectoral Sandpipers illustrate that nicely, with feet larger than their heads!

Adding to the appeal of a fluffy newly hatched shorebird, they hatch with disproportionately large legs. These Pectoral Sandpipers illustrate that nicely, with feet larger than their heads!

 

Fuzzy adorable shorebird chicks – does it really get any better? About 3-4 days ago many of our nests began to hatch, so now each day on the tundra is occasionally punctuated by a small troop of chicks with accompanying parents. As we spend the summer up here watching shorebirds go through the nesting process, the amount of hardship that these impressive little birds face never fails to amaze. I wish I could tell their side of the story, but I can only give you the view of a shorebird researcher.

The world from the viewpoint of a newly hatched Pectoral Sandpiper. Tundra grasses and sedges that seem inconsequential to us form a towering "forest" that needs to be navigated until they are airborne.

The world from the viewpoint of a newly hatched Pectoral Sandpiper. Tundra grasses and sedges that seem inconsequential to us form a towering “forest” that needs to be navigated until they are airborne.

 

When we arrived here at the beginning of June, the world was made of snow and ice. Summer seemed impossibly far away, and yet the birds that brought us here had already been present for a week or more. Feeding at the margins of ice puddles, they eked out an existence on the insects that are hardy enough to tolerate the same conditions. This year the earliest egg laid in a nest we found was a Pectoral Sandpiper that laid the first of its four eggs on May 31 – truly impressive! Over the next week as the 80% snow cover rapidly recedes, the shorebirds jostle with other members of their species to compete for territories and mates. For some species, such as the Semipalmated Sandpiper and Dunlin, males return to the same territories year after year, and will often pair up with the female if she returns as well. This site fidelity really makes our lives easier, enabling us to use previous nest locations of marked birds to narrow our search for their nests this year.

Lapland Longspurs are our only breeding songbird here most years, and they often lay their first eggs in the range of May 25-27. They have to find small patches in what is an almost entirely white landscape. We stumble across many of their nests throughout the summer, but shorebird chicks win out every time in my opinion.

Lapland Longspurs are our only breeding songbird here most years, and they often lay their first eggs in the range of May 25-27. They have to find small patches in what is an almost entirely white landscape. We stumble across many of their nests throughout the summer, but shorebird chicks win out every time in my opinion.

 

After the battling for territories and mates has finished, it is time to actually nest. Each species has its own specific habitat preferences, and once you get familiar with the birds, you can often look at an area and know where you will have the best chance of finding a nest of any given species. Semipalmated Sandpipers like drier habitats, often on the dry rims of tundra puddles or near the edges of ponds. They often line their nest with a certain type of white lichen that makes for some great home décor. Pectoral Sandpipers and Dunlin are more varied in their habitat choices, but usually opt for a bit marshier and damper locations, closer to water and sometimes on little rises in the middle of a mostly wet area. Phalaropes, both Red and Red-necked, are the water specialists. Almost invariably within a half-meter of a wet ditch or pond, their nests often have grasses pulled over them in a dome, rendering the eggs and incubating bird nearly invisible from above. Each bird chooses their nest location and gets down to business.

This Red Phalarope nest was unusually exposed to any creature viewing from above - perhaps not so good for the nest, but hopefully good enough! This nest is still active as of now, and could be hatching in the next 2-3 days. Right on the edge of a wet polygon ditch, the nest location is exactly as would be expected for this species.

This Red Phalarope nest was unusually exposed to any creature viewing from above – perhaps not so good for the nest, but hopefully good enough! This nest is still active as of now, and could be hatching in the next 2-3 days. Right on the edge of a wet polygon ditch, the nest location is exactly as would be expected for this species.

 

All the nests will top out at four eggs, the most efficient number for conserving heat and fitting nicely under an incubating bird. The eggs are generally laid one per day, and once the fourth egg is laid, the incubation process begins. For about 20-26 days, depending on the species, the eggs will be kept warm underneath the parent bird. Semipalmated Sandpiper and Dunlin pair members both take turns with incubation duty, as opposed to Pectoral Sandpipers and the phalaropes, where the burden falls on one bird. Female Pectoral Sandpipers care for the nest and any resulting offspring, and the reverse is true in phalaropes, where the males are the sole parental presence. Leaving only for brief feeding breaks or to avoid a predator, the incubating birds will spent their 3+ weeks on nest duty before hopefully having a brood of young to tend to.

This brood of Red Phalaropes will be raised entirely by the male parent, tended to for a couple weeks before being left to fend for themselves. Within a day of hatching they will have left the nest and are able to swim, run, and feed in the challenging tundra landscape.

This brood of Red Phalaropes will be raised entirely by the male parent, tended to for a couple weeks before being left to fend for themselves. Within a day of hatching they will have left the nest and are able to swim, run, and feed in the challenging tundra landscape.

 

With 2-3 days left before the chicks leave their shelled abodes, they face the first hurdle of their lives – exiting the egg. Using a hardened protrusion on the tip of their beaks called an “egg tooth”, each chick must break its way out into the world. From the outside this appears as a spiderweb of cracks visible on the surface of the egg, which we look for in our nest checks as a sign of chicks soon to come. Initial haphazard cracks eventually converge into a star pattern that radiates out from a central point, known as a “star pip” for its star-like appearance. The next step is when a flake of the shell is actually popped out into the nest, leaving a tiny hole, or “pip”, in the egg. This hole will eventually widen and be at the location of the passageway out of the egg. After the chick finally chisels its way out and flops damply into the nest cup, the parent carries away the now purposeless egg and incubates the new chick and remaining eggs. This process is repeated until all chicks are fluffy and happy, and eggshells are absent. After several hours in the nest cup, the squadron of parents and young leaves the nest, never to return.

Sometimes when we go to check the nests for signs of hatch, we get to watch the process before our eyes! A hatch check involves checking each egg for signs of pipping or cracking, and when I picked this egg up, a little beak was furiously working on the egg from the inside, chipping its way to freedom.

Sometimes when we go to check the nests for signs of hatch, we get to watch the process before our eyes! A hatch check involves checking each egg for signs of pipping or cracking, and when I picked this egg up, a little beak was furiously working on the egg from the inside, chipping its way to freedom.

 

The chicks will stick close to the parents for a few days, learning how to feed and exist in the tundra environment, but after a couple weeks they are on their own. With still over a week until they are able to fly, these half-grown chicks are left to fend for themselves as the parents make their way to migration staging areas, beginning the long migration south. These “teenage” chicks often form little roaming groups with other young of their same species, wandering around the tundra with their compatriots for a few days before eventually parting ways as they head south in the wake of the adults.

This Semipalmated Sandpiper chick is a few days old, photographed feeding along the edge of a small stream with its three nest-mates and parent in attendance. In just a few weeks it will be heading south on the first of many long migration journeys.

This Semipalmated Sandpiper chick is a few days old, photographed feeding along the edge of a small stream with its three nest-mates and parent in attendance. In just a few weeks it will be heading south on the first of many long migration journeys.

 

Most people don’t glimpse the annual cycle of shorebird life until this stage – when our beaches are speckled with migrant birds. In the local Manomet area there are several important migration stopover sites that can be excellent places to encounter large numbers of shorebirds taking advantage of the natural resources. Plymouth Beach in Plymouth (MA) and the South Beach/Monomoy NWR complex in Chatham (MA) can both harbor thousands of shorebirds at any given time, and perhaps some of the same individuals that we see up here during the summer! Next time you’re on the beach, keep an eye out for any shorebirds that might be stopping by – perhaps with a newfound appreciation of where they’ve come from and what they’ve done!

 

Death from Above

In the fifth and final year of work at the Canning River  for the Arctic Shorebird Demographics Network (ASDN) , one would expect to have a good idea of what the birds will be doing in any given year.

This Pomarine Jaeger keeps watch near our camp under the light of the 2am sun with the Brooks Range looming in the background. At the top of the food chain around here, this bird has little to worry about except where the next meal is coming from.

This Pomarine Jaeger keeps watch near our camp under the light of the 2a.m. sun with the Brooks Range looming in the background. At the top of the food chain around here, this bird has little to worry about except where the next meal is coming from.

 

So far the first two weeks of this season have been full of surprising and unusual trends, both with the numbers of certain species nesting and the behavior of those species. The changes we are seeing now in the early part of the season show how important it is to collect long-term data in vital locations like the Arctic. Even in a short few years we are gaining new insights into the lives and ecology of these species that would be impossible to ascertain in a single field season.

The Pomarine Jaeger featured in the first picture is a light-morph bird, whereas this one certainly belongs to the dark-morph category. Dark-morph Pomarines supposedly make up less than 15% of the total population, but we have found a fair number in the area.

The Pomarine Jaeger featured in the first picture is a light-morph bird, whereas this one certainly belongs to the dark-morph category. Dark-morph Pomarines supposedly make up less than 15% of the total population, but we have found a fair number in the area.

 

There are five species that we call our ‘focal species’ and they are the birds we concentrate our efforts on. These birds are: Semipalmated Sandpiper, Pectoral Sandpiper, Dunlin, Red-necked Phalarope, and Red Phalarope. The number of nests that we find for each of these species varies from year to year, but we usually recover around 60-80 Semipalmated Sandpiper, 8-15 Dunlin, 30-60 Red-necked Phalarope, and 30-60 Red Phalarope nests.

The Pectoral Sandpiper, the one species not listed above, is the most unpredictable of them all. Pectorals show less site faithfulness compared to the other four focal species, so we haven’t seen the same birds returning year after year. Their wandering tendencies mean that some years we have recovered few and in other years we have recovered many.

Our lowest nest recovery in a season was less than 20 Pectoral Sandpipers nests, but the high record before this year was around 80 nests. As it stands on June 17, we have found 93 Pectoral nests, and we could easily exceed 130 nests this season for this one species alone.

One nesting Parasitic Jaegers takes a break from defending the nest for a moment. This is an intermediate-morph bird and is almost halfway between the light and dark coloration shown in the Pomarine photos before this.

One nesting Parasitic Jaeger takes a break from defending the nest for a moment. This is an intermediate-morph bird and is almost halfway between the light and dark coloration shown in the previous Pomarine photos.

 

Aside from our focal species, the other winged residents of the study area vary in abundance between years. This year we have noticed an unusually large number of aerial predators in the area. The most common predatory birds in Canning River are the three species of jaegers (Pomarine, Parasitic, and Long-tailed), Short-eared Owls, and Snowy Owls. There are also some Rough-legged Hawks, Northern Harriers, and Peregrine Falcons that travel 30+ miles from the mountains to hunt the coastal plain.

Normally we will see small numbers of Pomarine and Parasitic Jaegers daily, with Long-tailed Jaegers showing every couple days in singles or small flocks, and Short-eared and Snowy Owls every couple of days. This year we have seen all of these species almost every day, and we saw 60+ Pomarine Jaegers and seven Short-eared Owls in one day! We have also found single nests of Pomarine and Parasitic Jaegers and Snowy and Short-eared Owls already, and it is likely that there will be more on the way.

This Parasitic Jaeger was hunting low over the tundra, keeping an eye out for a wayward lemming or perhaps an unsuspecting shorebird. Pairs of this species will often team up on a single shorebird, taking turns pursuing the quarry until a successful hunt is completed.

This Parasitic Jaeger was hunting low over the tundra, keeping an eye out for a wayward lemming or perhaps an unsuspecting shorebird. Pairs of this species will often team up on a single shorebird, taking turns pursuing the quarry until a successful hunt is completed.

 

So what does the presence of all these predators mean for the shorebirds? The predators are mostly here to feed on lemmings, but they will take a bird every now and then if a chance presents itself. The most striking response to this new threat is that we have noticed the shorebirds completely changing their behavior around the nest. Compared to the behaviors we have observed over the past four years, it’s like we’re dealing with different species!

Semipalmated Sandpipers normally fly away when we are within 5-30 meters of the nest, which gives us a good distance to maximize nest-finding success. Pectoral Sandpipers are usually more sensitive to us than the Semipalmated Sandpipers are and often fly away when we are 30-80 meters away, which makes it much more difficult to locate the nests because the possible range is larger.

This year all of the species are sitting much longer on their nests. The Semipalmated Sandpipers are seeming to stay on their eggs until we are 1-8 meters away, and Pectorals are flying away when we are 15-30 meters away.

This means that we are finding many fewer Semipalmated Sandpiper nests than average (34 to date), and lots of Pectorals (up to 93 nests as stated above). Phalaropes nest later than the other species, so it is still early to know how their behavior will be affected, but the changes so far are nothing short of fascinating.

The interesting thing is that many of the birds that are showing different behavior this year are returning individuals from past years. This suggests that they are able to adapt their behavior on a local scale based on the predators that are present each year – pretty amazing! It sounds like a graduate research project just waiting to be done.

A lone male Common Eider flies eastward in the company of six females - perhaps looking to settle somewhere.

A lone male Common Eider flies eastward in the company of six females – perhaps looking to settle somewhere.

 

Many of the other species here are also susceptible to the presence of predators. The waterfowl that nest here are a prime example of this. The nesting Cackling Geese and Brant often fall victim to marauding Arctic Foxes as do the King Eider and Northern Pintail that make up most of our duck nests.

We also see Common Eider occasionally, and the rare Spectacled Eider has nested here once during the study. So far this year we have seen three pairs of Spectacled Eider, but no sign of nesting yet. Eider show some of the most stunning plumage that you could ever hope for in a duck, and their fluffy down is world famous.

Spectacled Eider is a spectacular bird in every sense of the name. Baby blue eyes and a shaggy mullet are unusual adornments on a bird, but these guys somehow seem to make it work.

Spectacled Eider is a spectacular bird in every sense of the name. Baby blue eyes and a shaggy mullet are unusual adornments on a bird, but these guys somehow seem to make it work.

 

As we start to discover more shorebird nests, we will see the effects of Arctic Foxes and avian predators on the remainder of the nesting period.

It is a tough life on the tundra, for any bird or organism. As I write this from the interior of our cook tent, the wind is howling around 30 mph outside, the temperature is in the mid 30′s, and the summer solstice is less than a week away. But I, like the birds, wouldn’t trade it for the world.

The King Eider is a beautiful duck with its ornate and improbably shaped head to the striking plumage on the rest of its body. Despite being one of the most common ducks in our study area we rarely find nests, and the ones that we do find usually fall prey to a jaeger or fox.

The King Eider is a beautiful duck with its ornate and improbably-shaped head and striking plumage. Despite being one of the most common ducks in our study area, we rarely find nests, and the ones that we do find usually fall prey to a jaeger or fox.