Friday, November 16, 2018

Killin' It

She's waving at us! Photo by Emily Stone.

“That’s a sighting for the history books!” Excitement crackled through Captain Mike’s voice as it boomed over the tour boat’s sound system. Eager passengers on the Kenai Fjord Tour clung to the deck railing and stared into the waves, hoping to catch another glimpse. The gracefully arched dorsal fin of a female killer whale cut through the ocean’s surface one last time before vanishing.

Countershading is a common pattern of camouflage in which an animal's coloration is darker on the upper side and lighter on the underside of the body. The wavy shape of their white belly also helps obscure their outline and their size when viewed from below. Photo by Emily Stone.
A few minutes earlier that killer whale had been playing almost directly below our admiring eyes. She started with a wave of her flipper, turned a few somersaults to show off the smooth white shapes on her belly, and then swam at the surface to give us an extra-good look. Such fluid grace in such a large package is a recipe for awe. We saw several more pods throughout the day, plus humpback whales, sea lions, puffins, and more, but none came as close as this.

Why would this creature of the sea spend time at the surface? It’s easy to look at their fish-like body and forget that killer whales need to breathe air. Of course, seeing the misty spray of their spout should jog your memory. Killer whales are toothed whales, and are the largest members of the dolphin family, which are mammals. It’s a fact I’ve been hearing since grade school, but it’s a fact that refuses to stick. These are smooth-skinned, fin-flipping, deep-diving, cold-water mammals.

Can you see the mammals in the kayaks? Photo by Emily Stone.

It’s no secret that I’m a mammal and I love jumping into cold water (Lake Superior and Boundary Waters lakes especially), but I generally spend just a few seconds scrubbing off layers of camping grime and then pop back out with a gasp. I watch warm-blooded loons diving all summer, but their well-oiled, heat-trapping feathers look dry even as they emerge from a dive. The body of this killer whale was smooth and dripping wet.

Near Seaward, Alaska, water temperatures go from a low of 39 degrees in March all the way up to 58 degrees in August. But even an 80 degree swimming pool feels cold to us when we first jump in. Water conducts heat about 25 times faster than air of the same temperature, and washes the warmth away from a body. According to Captain Mike, the water is so chilling that harbor seals pull out onto ice floes in order to warm up in the sunshine! Indeed, the floating ice of one glacial bay we explored was dotted with groups of seals. Many of them looked a little bit like bananas—their heads and flippers held up off the cold surface. Hauling out on ice floes also leaves seals inaccessible to land predators and less visible to their most common predator: the killer whale.

Banana-shaped harbor seals on an ice floe. Photo by Emily Stone.

Killer whales are all fierce predators, but not all killer whales eat seals. The gregarious, easily-seen “resident” populations of killer whales (like the one who I saw surface) focus on catching fish like chum and chinook salmon in a nearshore environment. This makes them a favorite of tour companies.

In contrast, transient populations of killer whales feed on seals, sea lions and porpoises. They may live in the same neighborhood, but they have to be stealthy and secretive in order to sneak up on their intelligent prey. While offshore populations of killer whales are the least-studied, it’s their diet of sharks and large pelagic fish that may have earned their species its name. One theory is that Basque whalers named them “killer of whales” after observed pods of orcas hunting baleen whales.

Some people prefer to leave out the “killer” in their title and call them orcas, in reference to their scientific name, Orcinus orca. In Latin, orca can mean either a large-bellied pot or jar, or a whale.

Large-bellied indeed! No matter what they eat, it’s remarkable that killer whales don’t need to eat more than a land mammal of the same size in order to keep their furnace running hot. Their large size and low surface-to-volume ratio help retain body heat. A thick layer of blubber under their skin adds more insulation. Using an adaptation that is shared with the ducks still migrating through our marshes and the chickadees flitting among snowflakes, orcas use countercurrent heat exchange to allow warm blood flowing to their extremities to heat up cold blood flowing back toward their heart.

On a chilly walk out in the woods today, my hands and toes went cold, but my core stayed warm. A diving killer whale will likewise send blood from its skin to its core to help retain heat.

Another important heat-conserving adaptation these marine mammals count on is that while they have to breathe air, they don’t have to breathe very often. On a cold winter day, we humans breathe an average of 12 to 20 times per minute while resting. Each breath brings cold air in and lets warm air escape. Resting orcas breathe only about 3 to 7 breaths every 5 minutes, and every breath is a conscious choice.

Killer whales must choose to come to the surface to breath. Photo by Emily Stone. 

As a fellow mammal who enjoys cold water, I feel a bit kinship with these great beasts. They are said to be the most widely distributed mammals in the world (aside from humans), and I do love to find those far-flung connections. As a Midwesterner, though, who grew up in an ocean of prairie, most sea creatures seem like aliens from the deep. Captain Mike was right; this sighting was one for my history books.

Now you can also listen to Emily’s columns as podcasts on Google Play or iTunes! Sponsors needed!

Emily was in Alaska for the summer. Follow the journey in this column, and see additional stories and photos on her blog:

For 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new exhibit: “Bee Amazed!” is open.

Friday, November 9, 2018

Ptarmigans on Top of the World


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Damp oak leaves crinkled under my boots, but few other sounds broke the North Country Trail’s tranquility. Then the whump-whump-whump of a ruffed grouse drumming filled my chest. It’s a sound usually associated with spring, but this male had a legitimate purpose. As young males leave their brood and seek a territory, established males reassert their claims, effectively telling the youngsters to move on.

The sounds of grouse—even the startling ruckus they cause when flushing—are a quintessential part of the Northwoods. But I wonder if they would sound odd to an outsider? This summer in Alaska I met some cousins of our ruffed grouse, and boy did they sound odd to this outsider!

The day after my amazing experience under the northern lights dawned frosty and clear. I continued driving north along the Taylor Highway and then east on the Top of the World Highway. As I neared and then crossed the Canadian border, it became clear that the road was aptly named. The views across rocky, round-topped hills were spectacular and generally unobstructed by trees. I pulled over at every opportunity, and at one turnout I found a dirt road scraped into the tundra that disappeared over a distant edge. With the childhood favorite “The Bear Went Over the Mountain” running through my head, I started walking.

Top of the World Highway just across the border into the Yukon.

Soon another sound cut in. An odd series of hollow little clucks and rattles emanated from a patch of lichen-crusted rocks. Was there a friendly alien hiding nearby? Or maybe a Star Wars character that only Han Solo can understand? With short, jerking movements the identity of the chatterboxes materialized from the camouflage: ptarmigans.

Our ruffed grouse grow comb-like bristles on the sides of their toes to provide snowshoe-like floatation and traction on icy aspen twigs. In contrast, ptarmigans have feet so fuzzily covered in feathers that their genus, Lagopus, means “hare-footed.” They are well-suited to the tundra habitats they prefer.

Close-up of a rock ptarmigan's feathered feet. Photo by Emily Stone.

Look closely at the feet of this spruce grouse--you can see the pectinations on his toes! Photo by Emily Stone.

Can you see the fringe of pectinations on the sides of these ruffed grouse toes? Photo By Emily Stone.

All grouse and ptarmigan seem well-adapted for snow-shoeing. 
Alaska is home to three species of ptarmigans. White-tailed ptarmigans seek out alpine neighborhoods with marmots, mountain goats, and Dall sheep. Their range is limited to North America. Willow ptarmigans prefer the lush vegetation of streamsides and marshy tundra. Rock ptarmigans prefer high elevations and latitudes where sparse vegetation reveals their namesakes. Both willow and rock ptarmigans are circumpolar, and can be seen in Scandinavia, Russia, Japan, Scotland, and the Alps.

A willow ptarmigan in Denali National Park.

Peering through my camera, I could barely pick out birds among the rocks. Fine bars of dark and light brown, flecked with white draped over one bird’s top half, while pure white pantaloons peeked out underneath. A scarlet eyebrow labeled that one as a male. Most other birds in this flock of a dozen or more lacked that conspicuous eyebrow and had brown patterns extending much lower—females and young. Based on the location, and the fact that willow ptarmigans would have been more rufous brown, I guessed that these were rock ptarmigans.

Male rock ptarmigans keep their white feathers longer into the breeding season. Photo by Emily Stone.

Ptarmigan seem tricky to identify by their plumage, though, because it is always shifting with the seasons. Most birds have just two different plumages per year—breeding and non-breeding. Ptarmigans moult three times a year in order to stay camouflaged in the ever-changing tundra. A pure white winter coat is the classic look for all rock ptarmigans. Only the outsides of their tails and a stripe from eye to bill remain dark. When spring winds whisper, males don an avian tuxedo in the form of dark feathers on their head and neck, and they strut about with red combs inflated. Meanwhile, females fade into the background with mottled brown and flecks of white. They are so well-camouflaged that Arctic foxes have been observed walking right past them.

Female rock ptarmigans have such amazing camouflage that they are hard to spot from even a few feet away. Photo by Emily Stone.

As the snow melts, the remaining white feathers on males’ bellies really stand out. In fact, their breeding plumage may be a little too eye-catching. The predation rate on male ptarmigans skyrockets during breeding season. That’s probably why they roll in the dust as soon as their mate begins egg-laying. Using this style of camouflage, bachelors and polygamous males can precisely customize how long they stay sexy in order to maximize breeding opportunities. Once they’re safely dirty, a full moult into summer browns can proceed at their leisure. Finally, both males and females gain grayish feathers for fall and then almost immediately turn back to white for the winter.

 Of course I didn’t know all of that as my eyes were going crossed trying to see these amazingly camouflaged birds among the rocks. I just enjoyed their odd sounds and the “Where’s Waldo” game of trying to spot them. Although the ptarmigans were nearly invisible, they were also pretty tame. It’s no wonder that they are an important game bird in the far north and have been named the official bird or game bird for Nunavut, Newfoundland, and Labrador.

Ptarmigan were also important to gold miners trying to survive brutal winters in the late 1800s. Earlier that morning I’d passed through an old gold mining town that wanted to honor the tasty birds who kept them alive through long winters. Unfortunately, Ptarmigan proved too hard to spell, so they ended up naming their town Chicken—just one more thing on the tundra that sounds odd to an outsider.

One of many giant chickens in Chicken, AK.

Now you can also listen to Emily’s columns as podcasts on Google Play or iTunes!

Emily was in Alaska for the summer. Follow the journey in this column, and see additional stories and photos on her blog:

For 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new exhibit: “Bee Amazed!” is open.

Saturday, November 3, 2018

Natural Connections now a Podcast!

Natural Connections articles are now available as a podcast each week! 

Each 6-7 minute episode features Emily reading her column. Occasionally you'll be treated to bird songs and other sound effects to enhance your experience. 

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Friday, November 2, 2018

The Challenges of Rain

Even when it wasn’t raining, mud splattered the windows every time a semi-truck passed us on the Dalton Highway. Every so often Tessa, a grad student from the University of Alaska Fairbanks volunteering on her lab-mate's project, or I would get out and wipe off the worst of it with a grubby towel, just to make sure we could carry out our duties as caribou counters. When we actually spotted a caribou, though, we had to roll the windows down to use our spotting scope and rangefinder. Thin clouds of the summer’s last mosquitoes floated in and out but weren’t aggressive about biting.

Overall, that first day of caribou counting was a little underwhelming. Driving 132 miles on a wet, bumpy, rutted, gravel road is not a very elegant way to travel. Looking back at photos I know that I had several sunny days throughout my summer in Alaska, but it’s the rainy ones that challenged my attitude and still cloud my perception.

There was at least one bright spot, though.

Halfway through our day, a dark shape materialized up ahead, in the space between the road and tall thicket of willows. I’m sure Tessa recognized it before me, but she just put on a little smirk and waited for me to figure out the blob’s identity. Soon the shaggy brown hair, stocky body, and slight hump resolved into what I knew from photos must a muskox. After that, we saw herds of muskoxen every day.

When I zoomed in on my photos later, I could see clumps of the muskox’s woolly underfur–still in the process of its summer shed—clinging to its shoulders. This soft “quiviut” is finer than cashmere and both warmer and stronger than sheep’s wool. It is a highly prized fiber, with a price to match—between $40 and $80 per ounce. The coarse hair that covers the wool grows to be the longest hair of any North American mammal. Also clinging to that hair was a swarm of hungry mosquitoes.

The thick hair of muskoxen protects them from the extremes of -40 degree winter winds, as well as clouds of summer mosquitoes on the summer tundra. Photo by Emily Stone.

A muskox’s thick coat is good for more than just fine scarves and bug protection, though; it also allows them to function normally in temperatures down to -40 degrees Fahrenheit with high winds. That’s important for a year-round resident of the Arctic tundra.

After crossing to Alaska on the Bering Land Bridge about 90,000 years ago, muskoxen found refuge in the far north away from the early hunters, as well as roaming as far south as Kansas. After the glaciers retreated, the muskoxen expanded. Along with bison—only a distant relative despite their similar appearances—the muskox was one of the few species who survived the extinction of Pleistocene megafauna.

As strange as these animals may seem to us southerners, theirs is a familiar story. By the late 1800s, muskoxen had been hunted out of Alaska. Their classic defensive technique of backing into a tight circle made it too easy for early hunters. By the 1920s, only Arctic Canada and East Greenland still held populations of this iconic animal. In 1930, reintroduction efforts began in Alaska. The first animals were brought to Nunivak Island, allowed to thrive, and transplanted from there to likely habitats in northern and western Alaska. Muskoxen were also reintroduced to Quebec, Svalbard, Western Greenland, Norway, and Russia.

Both male and female muskoxen have horns, but males like this one grow a thick boss at the base of each horn with little space in between. Photo by Emily Stone.

The next chapter in their story is also unfortunately familiar. Recent research indicates that their populations are at risk due to climate change. The culprit seems to be rain-on-snow events that encase the tundra vegetation in ice. While rainy days challenged my ability to keep a positive attitude all summer (and to see mountains), rainy days may also be challenging the muskox’s ability to survive. Through the short summer, muskox browse on grasses, sedges, and willow leaves. For the rest of the year, these big animals must use their acute sense of smell and big, round hooves to paw down through the snow to find their food. It’s tough work.

Big weather events provide a stunning example of the problems that ice can cause for muskoxen. In 2003, twenty thousand muskoxen starved after a rain-on-snow event prevented them from reaching food. (Ruffed grouse share a similar fate in Wisconsin, where crusty snow can prevent them from using insulating snow caves. Athletes and organizers of the American Birkebeiner Ski race can also attest to the problems cause by winter rains.)

Even a slight increase in winter rains can reduce the ability of pregnant muskoxen to find food. Their calves are born smaller, stay smaller, are more vulnerable to starvation and disease as they grow, and take longer to produce their own calves. Even though those are sub-lethal effects, they may have a dire impact on muskox herds into the future.

Their Arctic habitat is warming at twice the average global rate. Could these big, lumbering beasts be canaries in the oil field?

The animals haven’t given up yet, though. As Tessa and I pulled over to observe a herd, we noticed a big bull following a cow nose-to-tail. The rut had begun, and the cow was probably in or near estrus. Later, I filmed him aggressively rubbing his pre-orbital gland on the ground vegetation—a dominance display aimed at other males. The muskoxen themselves are doing all they can to survive. The real question, then, is what will we do to help moderate the changing climate?

The Muskox rut begins in August and lasts through October. Bulls will follow cows, and they will also battle for dominance with other bulls by charging at each other and colliding squarely at the base of their horns. Photo by Emily Stone.

Emily was in Alaska for the summer! Follow the journey in this column, and see additional stories and photos on her blog:

For 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new exhibit: “Bee Amazed!” is open.