Three winter surprises

An unusual bird, an unusual mammal, and midwinter construction

Regular bird-watchers spotted an unusual bird in Auke Bay this winter—an American coot. Although range maps show occasional migrants in southern Yukon, at the present time the Auke Bay record is the most northern, according to ebird. Coots are members of the rail family, which includes the sora that is often found in the Pioneer Marsh in summer. Most coots breed farther south of here, but there are isolated breeding populations in east-central Alaska and southern Yukon; this individual is presumably doing its winter things and may migrate north later.

American coot (cleaning up the harbor?) Photo by Kerry Howard

Although they sometimes use salt or brackish water on migration, coots typically nest in freshwater marshes with fairly deep water and lots of tall vegetation. They eat mostly aquatic vegetation, but also take small animals, both invertebrates and vertebrates, at times. Food is gathered by dipping the head underwater or by diving, and usually brought to the surface for swallowing. They sometimes feed on carrion, or steal from ducks, or even snatch flies out of the air. They are strong swimmers; they don’t have fully webbed feet but they have toes with lobes on the sides that increase the size of the foot paddle. 

Coots are strongly territorial, vigorously defending a nesting territory again other coots, as well as ducks, grebes, and sometimes other birds. They are socially monogamous, but in some populations there seem to be floater females that lack a mate and a territory and these females sometimes dump their eggs in the nest of a mated pair. Nests are placed on floating platforms of vegetation, often anchored on the sides by tall cattails and reeds. Multiple platforms are built by each pair and used for courtship, and one is used for the nest. The nest itself is made of small bits of vegetation, making a smooth basket big enough to hold the eggs, although this tends to get trampled flat by the time chicks are present. The floating platform tends to sink, so the parents have to continually repair and augment the structure.

A normal clutch size is about eight to twelve eggs per nest; larger clutches are probably due to the activities of egg-dumpers.However, most of the dumped eggs do not produce chicks, because the nest-owners usually reject the excess eggs. Both parents incubate the eggs, the males mostly at night. Incubation takes a little over three weeks, and the eggs hatch over a span of about three days. Chicks can hop out of the nest and swim around just a few hours after hatching, calling loudly for food to be delivered. Long ago, when I was doing my thesis research in the marshes of eastern Washington, I was fascinated by the goofy appearance of those little chicks, as they swam around after the parents. They have thick black down feathers with stiff, curly, orange tips, a nearly bald head, with some bluish patchesabove the eyes, that’s fringed with red or orange frizzy feathers, and a mostly red bill. It turns out that the oddball coloring is important in stimulating the parents to deliver food. Young birds are chased out of the parent’s territory after about three months, to live on their own and mature at age one year.

Also appearing this winter is another critter that is rare around here: Fishers live in northern forests across North America, but only recently (since the mid 1990s) have they been recorded in Alaska and southern Yukon. These pioneers are thought to arrive via the Taku River valley. Fishers belong to the weasel family (Mustelidae), smaller than wolverines but larger than marten. They climb well, because (like squirrels) they can rotate their hind feet so the toes point back; they are active year-round. Like other members of this family, they are fierce predators, capturing mostly rodents, hares, and grouse, but also eating carrion, insects, and fruit—but not usually fish, despite their name. Fishers are very good at killing porcupines, biting the face and then flipping them over to rip open the belly. They also sometimes prey on marten and weasels, and research has shown that these smaller mustelids tend to avoid times of peak foraging by fishers.

Fisher. Trailcam photo courtesy Riley Woodford

Although males and females mature at age one year, most successful breeding starts at age two. Dens for mothers and kits are usually in cavities in big logs and trees. Kits are generally born in early spring, and females come into estrus and mate a few days later. Sperm meets eggs and a fertilized zygote is formed, but it does not develop very much right away; instead, it just rests in the uterus until late winter, when it is implanted in the uterine wall and active development begins. Litter size is commonly two or three kits, weighing less than two ounces each, which depend on mother’s milk for at least three months and may be weaned at four months. By early fall, they are about full grown; males usually weigh about twice as much as females.

Trailcam photo courtesy Jos Bakker

One more little surprise: a trail cam in the Dredge Lakes area has recorded significant beaver activity in the middle of winter, despite heaps of snow and some very low temperatures. Small trees have been chopped down and hauled away, presumably for food. We seldom see winter activity like this around here. Adult beavers typically live on stored fat reserves while remaining in the lodge in winter. However, kits keep growing through the winter months, and they need to eat. They usually feed on a cache of sticks in front of the lodge, but maybe this family didn’t make a big enough cache.

The hills of home

from Wisconsin to Alaska

I recently returned from a visit to the Midwestern locale where I grew up. There, the hills of home are very ancient mountains, now worn down to their stumps. Pink quartzite cliffs ring a deep, spring-fed lake. Moraines now stretch across both ends of the lake; this is where the last glacier terminated, thousands of years ago.

An Ice Age Trail loops for hundreds of miles across Wisconsin, following the former border of the glacial ice. A nice atlas of the trail provides detailed maps. I walked a portion of the trail, enjoying some old friends, such as Pileated Woodpeckers, goldfinches, chatty little Black-capped Chickadees, and jack-in-the-pulpit with its bright red fruits. I saw ‘real’ Blue Jays (not our Steller’s Jay, which is sometimes called a bluejay). Eastern bluebirds were feasting on wild grapes and the last of the black cherries, alternating between the cherries and a conveniently adjacent grape vine. Fall colors were well underway: sumacs and Virginia creeper in shades of red, and sugar maples glowing red and orange and yellow.

I came back to my Juneau hills of home, with its much more recent mountains, to find that the snowline had crept down to treeline. The low-lying blueberries and dwarf dogwood offered shades of red, cottonwoods provided gold and bronze, and muskeg sedges made brassy tones of orange.

On a walk on the shores of Mendenhall Lake, we encountered a surprising diversity of birds: three kinds of sparrows, hermit thrushes, two species of shorebird, three kinds of waterfowl including a flock of widgeon, some American Dippers, and magpies visiting from the Interior. Kinglets were gleaning vanishingly small insects from the willows; we inspected numerous willow twigs and couldn’t see more than one or two miniscule bugs. I was astonished to see, at this late date, a male and a female yellowthroat (migratory warblers that nest in marshes). They flitted around in the brush, occasionally zooming straight up into the air and catching what looked like small moths.

The sun—amazingly—came out from behind banks of gray clouds. Two ephemeral rainbows emerged from the base of Mt McGinnis and grew toward the glacier, and then disappeared in the same order. The sands of the beach showed signs of passage of beavers, caddis flies, and shorebirds. And no planes or helicopters disturbed the peace!

A happy sighting on the way was an American Coot, busily foraging in a slough and apparently being very successful. Coots are widespread across North America, but they are relatively rare in Southeast. They eat a wide variety of foods, including seeds, greenery, snails, and little fish. This particular coot was probably catching sticklebacks and caddis fly larvae.

American-Coot,-by-bob-armstrong-1
Photo by Bob Armstrong

I’ve never found a coot nest here, but they were common in the marshes of eastern Washington where I did a lot of fieldwork many decades ago. Male and female coots collaborate in building a floating nest of vegetation and in other aspects of parental care, right through until the chicks are independent. Young coot chicks are, to my eyes, very silly-looking: body covered with dark down, a ruff of orange and red fluff around the neck and base of the bill, setting off a totally bald crown. Coots defend their nesting territory with great vigor, charging at intruders with loud protests and excited splashing. The females have the unusual habit of dumping some of their eggs in the nests of other coots, and so letting somebody else raise part of the brood.

Coots are prey for many predators, including large gulls, owls, and hawks. In some areas, coots are the main prey of bald eagles. Around here, I see them occasionally in Twin Lakes, especially in fall, but then the eagles are generally busy elsewhere, filling up on salmon.