On Bessie Creek Trail

a soggy slog and crossbill thoughts

I tried to second-guess Juneau weather the other day. The Parks and Rec hike was scheduled for Mt Roberts, up to the tram and the cross. I figured that trail would be a nightmare of ice, so I (with a friend) opted to go out the road—where it is usually colder, they say. So we hoped that the rain-and-snow mix that was falling in town would be just nice falling snow in the colder zone out the road. Ha!

Wrong! Out the road it was raining. The temperature was several degrees warmer than in town. And there was even less snow on the ground out there. It doesn’t pay to try to second-guess our weather!

Nevertheless, there we were—way out the road. So we went up the Bessie Creek trail, which starts just past Adlersheim. The quagmires that mess up the beginning of the trail were largely frozen and elicited none of the usual bad words from us. The route through the forest was quite passable: some snow, a little ice, and some open ground. Cleats were useful but not absolutely necessary.

I think Bessie meadows are at an elevation of about six hundred feet. Alas, the new-snow line was tantalizingly just out of reach, about a hundred feet or so higher. However, the existing snow was plenty deep for good snowshoeing.

We put on our snowshoes when we reached the beaver pond and the main meadow and then we strolled around the beautiful, rolling meadow in the rain. Someday I’d like to do the whole route from the Bessie meadows down along the south fork of Cowee Creek to the mainstem of Cowee Creek, and thence back to the road.

Early morning snow and all-day rain had blurred most of the animal tracks, unfortunately. A series of paired, rounded paw prints, with about four or five feet between pairs, suggested a large sort of weasel-relative. Some other creature had plunged deeply in the snow, lunging forward, but I couldn’t be sure who it had been.

We found a horde of pine siskins on the ground at the edge of the forest. They were busily picking up fallen seeds and chattering to each other. There could easily have been a thousand of them. Our approach sent them flying, but they returned to the feast as soon as we went by.

I heard a gang of red crossbills, foraging in the treetops. I’d never really understood how the crossed bill-tips served to pry open cones. But a good video is available online from the Cornell University Laboratory of Ornithology; this makes it all very clear. Once the cone scale is pried up by the crossed bills, the bird extracts a seed and removes the wing by holding the seed in a palatal groove while the tongue helps work the wing off the seed.

These crossed bills are somehow also capable of picking up seeds and grit from the ground, just as do birds with ordinary, straight bills.

Red crossbills are widespread in North America, and may comprise a group of closely related species. Different types of crossbill are adapted to forage specifically on certain species of conifer cones; some have large bills and large palatal grooves for large cones with large seeds, and others have small bills and small palatal grooves for small seeds. Each type of crossbill can also feed on other species of conifer, but they are most efficient on their own type of cone. Their calls are also distinctive, to the trained ear, and they seldom seem to interbreed. Red crossbills, and the related white-winged crossbill, move around seasonally, appearing in large numbers in a certain place and then moving on in search of better foraging.

After several hours of soggily tramping around, we got back to the car, wet but happy. And the Mt Roberts hikers? Well, it seems I was not far wrong in thinking that trail was a misery.

Spring?

… it may be creeping up on us!

The days grow longer and we all start wishing that spring would be here NOW! Indeed, spring is slowly, slowly springing. Perhaps it got a bit confused by the lack of a real winter? Or perhaps we are just a tad over-eager.

There are, in fact, a few signs that the new season is upon us. The flocks of varied thrushes that fossicked about on the beach fringes have dispersed, and we now hear the familiar song from many points in the forest, as they set up their breeding territories. Song sparrows are singing, too, a trifle rustily, but soon to be in good voice. Steller’s jays are now seen commonly in pairs, and their calls are more varied than in winter, or so it seems. Hooters (sooty grouse) are heard again on the hillsides. The robins are back, but I have yet to hear their song.

The red-breasted sapsuckers are here, checking out snags and light posts, tapping on trees and houses. Canada geese are busily grubbing up sedges from the wetlands, picking off the sharp, protective tips of the new shoots and biting off the nutritious new growth. Various reports come in: I heard a ruby-crowned kinglet, saw an early hummer, heard a junco sing.

As the ice melts on my home pond, mallards again arrive, drifting in the bit of open water at the outlet, marching across the ice, scavenging spilled bird seed. Even though the millions (apparently) of pine siskins seem to prefer feeding on the massive spruce seed crop and the alder seeds, some of them visit the feeder hanging over the pond and messily select certain sunflower seeds, dropping hundreds onto the pond. Squirrels and mice, as well as the mallards, make good use of the rejects. And, I happily see ‘my’ nuthatches again, after a long seasonal absence.

The most exciting sighting in the bird way was a small flock of rusty blackbirds in the Dredge Lake area. As usual in my limited experience with them, they were poking about in a shallow, brushy pond. But I didn’t get to watch them for long; they soon moved deeper into the thickets. I don’t see them very often as they migrate through here to the north country. Unfortunately, their population has declined dramatically in recent decades, for unknown reasons, so they are getting harder and harder to see.

Rusty-Blackbird,-female,-by-Bob-Armstrong
Female rusty blackbird. Photo by Bob Armstrong

The plant world, too, is showing feeble signs of spring. Elderberry buds grow fat and shoots of cow parsnip peek up above the leaf litter. In some places, felt-leaf willow has borne fuzzy catkins for a week or two already. Blueberry shoots are ready to go, just waiting for the right moment. The first shoots of skunk cabbage to emerge from the muck were eagerly cropped by deer.

Mountain goats are back on the ledges near Nugget Falls. Beavers never really quit working this ‘winter’ but got busy every time the temperatures rose and the ice weakened. Bears, probably especially juveniles or males, have begun to emerge from winter dens: moms with cubs presumably wait somewhat longer, so the new cubs are strong enough to follow mom around the forest.

I can’t claim that spring has sprung, but it may be creeping up on us, all the same!

Pine siskins and common redpolls

winter-hardy seed eaters

During November, people often asked me about the flocks of little brown birds that were seen swooping in unison from tree to tree. Sometimes a whole flock would whirl up and take off for some other location. These flocks were often quite large, numbering 300 or more birds, and just how hundreds of birds can fly so close together without bumping into each other is a wonderment.

These small, brown, flocking birds are pine siskins, relatives of goldfinches and redpolls. In our area, the most similar species, with the same flocking behavior, is the common redpoll. However, the redpolls do not usually arrive until February or so, remaining until then in the cold Interior where they breed in the summer.

pine-siskins-fighting
Pine siskins. Photo by Bob Armstrong

Siskins and redpolls are the same size, roughly five inches long and weighing about half an ounce. Close up, you can see that siskins are heavily streaked with brown, with flashes of yellow in wings and tail. Redpolls are not quite so heavily streaked, and are distinguished by a red cap (as their name implies) and a reddish hue on the upper breast of the males (and no yellow flashes).

The yellow pigment in siskin feathers is produced by carotenoids, which birds cannot synthesize and so must obtain from their food. (Only a few birds, such as parrots, can make yellow pigments that are not based on carotenoids.) Carotenoids are found in leaves, fruits, insects (perhaps especially those that feed on leaves), and to some extent in seeds. In most yellow-feathered birds, the intensity of the yellow color depends on the amount of carotenoids the birds ingest; in some cases, chronic illness fades the colors.

Siskins vary in the intensity of the yellow flashes in wings and tail. There may be a tendency for males to have somewhat brighter yellow plumage than females, but this is said not to be a reliable indicator of gender, perhaps because the color depends on what the birds have been eating and how healthy they are.

common-redpolls-by-bob-armstrong
Common redpolls. Photo by Bob Armstrong

The red of redpoll feathers is also carotenoid-based. In this case, the ingested carotenoids are modified by the bird’s metabolism to produce red instead of yellow pigment. Mature redpoll males and females can usually be distinguished, because males (but not females) have a red patch on the upper breast, but young males may lack the red patch.

When siskins and redpolls come to Southeast, the flocks often festoon the alder branches, where the birds dangle acrobatically as they extract seeds from the cones. When we have an early-winter influx of siskins, foraging heavily on alder seeds, I have to wonder how much they leave for the later-arriving redpolls. However, both species also feed on many other kinds of seeds, including spruce, birch, assorted weeds, and thistle in backyard feeders.

Both species are known as ‘irruptive species’, because their numbers in any one region can vary enormously. When seed crops are good in an area, huge numbers of the birds may arrive; 2010 was a year of bumper crops of spruce and hemlock around here, and perhaps alder too. Good seed crops allow siskins to breed as early as February. But when seed crops fail, the birds range widely in search of better foraging. They may travel hundreds of miles, suddenly appearing in huge numbers in the Lower 48; siskins even may travel to the Gulf Coast in some winters.

The strong dependence on seeds is associated with other habits, too. We often see these birds on the ground at the edge of the road in winter, where they are apparently attracted by salt, and possibly grit. Siskins are known to come to other sources of salt, such as a block of salt that has melted onto a stump in someone’s backyard, or ash in a firepit. There may be something about a diet of seeds that creates a need for salt and minerals.

Siskins put on more winter fat than redpolls, increasing their body weight by around 33%, which helps them survive the low temperatures and short days for gathering food. When redpolls molt in the fall, their new plumage is thicker than the old, worn feathers, providing better insulation; this is probably true, at least to some extent, for siskins also. Redpolls also gain muscle mass at low temperatures, perhaps in relation to shivering.

Redpolls are able to burrow into the snow, creating tunnels over two feet long that lead to a roosting chamber a few inches under the surface of the snow. Several birds may share a burrow, where the snow provides an insulating blanket.

Both species have the capacity to store seeds in a pouch that opens off the esophagus. A pouch full of seeds helps a hungry little bird get through a long winter night. The storage pouch has other uses too. In the nesting season, a male can carry a pouch of seeds to his incubating or brooding female; the seeds are regurgitated directly into the female’s mouth as the beaks of the two birds are held close together and crosswise (not tip to tip). And both adults can regurgitate a mash of seeds and bugs into their growing nestlings.

Both species often forage at backyard feeders, favoring thistle seeds and sunflower kernels. Siskins seem to be particularly feisty and aggressive, quarreling with each other and even with the larger juncos.

Out and about

bits and pieces from December

I try to get out for a walk every day, whatever the weather, although the weather may determine the length and location of the outing. How much I see of natural history interest varies greatly, depending on many factors, including a perceived need to watch the footing in sloppy mud or on slippery ice or wet rocks, sometimes a wish to be a bit sociable, or even do some serious (or not-so-serious) thinking. But most of the time, I like to keep my eyes and ears open to what is around me. So here are some bits and pieces from December.

As a cold snap settled in, Mendenhall Lake grumbled and growled and muttered in a long-winded soliloquy—the ice, talking to itself as the water froze and expanded. Smaller ponds were less loquacious but still murmured and popped at a lower decibel level. Meanwhile, overhead, large flocks of pine siskins flitted from spruce to spruce, sometimes swooping high over the canopy before disappearing in the crown of another cone-laden spruce.

In between short periods of deep cold, however, we had spells of surprisingly warm temperatures, turning our little bit of snow to slush and sending meltwater down over the existing ice on streams and ponds. Open water formed at inlets and outlets of ponds and along the fringes of Mendenhall Lake. A reliable observer reported seeing a beaver swimming in Mendenhall River in late December, when local beavers are normally snug in their lodges, sleeping or nibbling from their winter cache of twigs. That beaver was not the only one escaping cabin fever: in several locations, I saw very recent tree-cutting and branch-gnawing that had not been there a few days earlier.

On the ground near Moose Lake I found several small wind-broken cottonwood branches, with the upper sides nicely de-barked. Some lucky gnawer had capitalized on this bonanza. But who was it? Not a beaver, although beavers had debarked a cottonwood tree trunk near the lake, leaving the marks of wide incisor teeth. Not a porcupine—the tooth marks were too small. But the marks were too big for a mouse. My best guess was probably a snowshoe hare; hares are generally fairly numerous in the area and the incisor marks were similar in size to the teeth in a hare skull in my collection.

porcupine-midden-pam
Photo by Pam Bergeson

Along the Treadwell Ditch are many trees, usually hemlocks, that show the marks of porcupine gnawing—tooth-marked, barkless patches, low on the trunk. This is a common sight around here, of course. I was particularly interested to find at least two trees that seemed to have been completely girdled sometime in the past. The bark had been removed all the way around the tree, which would interrupt the flow of water and nutrients between roots and crown, starving the roots of food and the crown of water. Yet these trees sported full crowns of needles and looked healthy. How could that be? The porcupines had removed all the outer bark and eaten most of the nutritious inner bark, but a meager, sketchy, brown network of inner bark was still visible. Could it be that enough strands of inner bark remained to connect the roots and the crowns? Hard to believe that would be enough to support a good-sized tree!

There are other little mysteries about porcupines and hemlocks. Some trees have obviously been visited repeatedly, in different years. Old chewings have partially healed, but new ones are there too. Are these trees particularly tasty? Also, I get an impression (untested, so far) that porcupine gnawing is more common on the uphill side of a hemlock trunk. Is that really so, and if so, why?

A special pleasure was seeing two humpback whales spouting as they cruised near Lena Point. They may have been late-departers for winter in Hawaii or they may have been among the few that overwinter here, feeding on herring (and any other luckless little forage fishes). Not on this day, but sometimes one can see a few sea lions swimming near the corners of a foraging whale’s mouth, trying to catch the fish that slipped away from the whale. The herring equivalent of ‘out of the frying pan, into the fire’!