Lazy day at Crow Point

porcupine shelter, bear sign, and winter berries

The tide was just starting to go out, leaving elegant wave marks in the sand. Otter and mink tracks were barely discernible amid the evidence of the passage of booted humans and their happy dogs. At the mouth of the river, a little cluster of gulls flitted up and own over the heads of two seals; there was obviously something edible there. A few buffleheads and a solitary Barrow’s goldeneye cruised the lower reaches of the river. Canada geese honked their way up the river, two by two; could they already be thinking about nest sites?

We found an old stump under which a porcupine had sheltered. A sizable pile of scat pellets filled a depression under the arching roots, and back in a corner, a cubbyhole offered protection from wind and rain. These pellets were more rounded, less oval, than usual for wintertime scat of porcupines, but we couldn’t think of any other creatures that would leave a latrine like this.

Possibly the most interesting observation was evidence of bear activity. In late February, this is a bit unexpected. But in this goofy pseudo-winter we are having, some bears in town have continued to be active and apparently never denned up to hibernate. So maybe all the signs of digging and eating out here fit right in with our mild weather.

In some places, the vegetation had been roto-tilled with shallow scoops that overturned mosses and roots. It wasn’t always clear what the foraging bear was seeking, but in several spots we found the exposed roots of chocolate lily (a.k.a. rice root). However, in each case, only some of the root material had been removed, leaving much seemingly edible stuff behind. That’s a little mystery that we’ve seen on several occasions—why dig it up if you’re not going to eat it?

A couple of bear scats contained only vegetation fibers. One also held partly digested highbush cranberry fruits. Because bears have short digestive tracts, food often passes through fairly quickly, and whole berries commonly come through. Another scat contained plump, juicy, bright red (undigested) berries of the plant called false lily of the valley (a terrible name! this plant does not resemble the real thing at all.)

The grassy berms behind the beach at Crow Point provide excellent habitat for false lily of the valley, and there was an abundant berry crop on view. Last year’s dead, heart-shaped leaves were gray, with black veins, and they set off the glowing red berries. These berries don’t get their fully ripe, bright red color until they’ve been well chilled. So berries produced last summer are conspicuous after a cold season and are then available for spring-arriving birds. It is interesting that this bear had not focused on the many berries that bejeweled the ground, but instead had spent its time digging.

Over a hundred Canada geese grazed in the broad tidal meadow. By walking close to the trees, we managed not to disturb their foraging. A few alert heads popped up to check us out but soon went back down to the business of eating. Earlier, an eagle had caused much consternation in this flock, but our passage left them calm.

While we were ambling down the beach, a stormlet blew in from the south, the sharp wind stirring up growing whitecaps. We were glad to put the wind at our backs when we left the beach to circle the grazing geese. Parka hoods up, shoulders hunched, we put on our ice cleats to trudge the icy trail back to the car.

Canada geese

migrants and residents among us

Most folks love to hear flocks of Canada geese flying overhead, especially in spring when the northward migrations pass over Juneau. Sometimes the flocks land in local wetlands to feed, fueling the next leg of the journey.

Geese-feeding-on-Lyngby's-Sedge-1-by-Bob-Armstrong
Photo by Bob Armstrong

On a mid-February hike near the scout camp, a small group of geese foraged in the meadow, and we managed to circle around them without sending them into an alarmed flight. Another small group flew in to join them, talking constantly with each other.

Several of the hikers remarked that it seemed rather early for the migrating flocks of geese to be here. Indeed it was! The geese we saw belong to a distinct sub-species, known as Vancouver Canada geese, that occupies Southeast Alaska and British Columbia year-round (although a few may migrate). In winter, we often see these residents on wetlands and in estuaries along Juneau shores. For instance, Echo Cove, the Cowee Creek estuary, Eagle Beach, the Mendenhall wetlands, and the Lemon Creek wetlands are often good places to see them.

Vancouver Canada geese are unusual in several ways (in addition to being here all year). They are larger than other subspecies of Canada geese; adults weigh an average of six to ten pounds in fall but even more in spring. And they nest in wooded areas, not in open areas such as marshes and tundra—habitats that are more typical of other subspecies; in short, Vancouvers have adapted to the commonly available habitats here in Southeast.

Nests are usually placed at the base of a pine or a group of pines in muskegs or at the base of a spruce or hemlock in denser forest. But sometimes, the nest is on a snag or even in a live tree. Nest sites can be far from tidal waters and are not usually adjacent to freshwater ponds; the nearest open water is likely to be a small, shallow forest pool. Whereas other Canadas escape to open water when disturbed, Vancouvers flee to cover in the forest. During the incubation period, the male may stand guard while perched high in a nearby tree; those great webbed feet somehow manage to let a big goose perch on a branch!

Other than residency, habitat, and body size, Vancouvers are much like the rest of the species. Males and females have similar plumage, but males are slightly larger. They reach breeding age in two or three years after hatching. They form long-lasting pair bonds; but if one member of a pair dies, the widow(er) may find a new mate. Each pair sets up a nesting territory, excluding other pairs.

Females do the job of incubating the eggs, for about four weeks, while the male keeps watch. There are usually four to six eggs in each clutch, but the average clutch size is smaller in nests that are started later in the season. Not much is known about nesting success, in part because the birds are so secretive and nests are hard to find. Even with radio-tracking, finding nests takes considerable effort. So it seems that only two studies of nesting success have been done, both on Admiralty Island, and the sample sizes are small (fewer than twenty-five nests in each study). A study in the 1970s found that eggs successfully hatched in fifty-six percent of monitored nests, and a later study found that about eighty percent of nests survived to hatching time. These estimates lie within the range reported for other populations. Canada geese whose nest is destroyed can sometimes renest in the same season, but the clutch size is smaller and obviously hatching time would be delayed. So juveniles would not be as well-developed when fall comes, but the consequences of such a delay have apparently not been studied.

After the eggs hatch, the goslings are able to walk, swim, and forage within a day’s time. They are guarded by their parents, which call out alarms if disturbed and shoo the young ones into cover. Sometimes, several broods of goslings are gathered together in what is called a crèche, and all the parents attend them. Goslings are able to fly after about eight or ten weeks, but they stay with their parents for a year.

After the nesting season, the geese molt and become flightless for several weeks while new flight feathers grow in. At least in some cases, birds seem to have favorite molting sites, probably not terribly far from where they nested, where they gather in flocks. I’ve paddled into Wachusett Inlet in Glacier Bay, for instance, and found the water surface littered with goose feathers (I soon retreated, so as not to disturb any still-flightless birds).

Canada geese are herbivores, eating a great variety of vegetation. Grasses and sedges are a mainstay in summer. In Southeast, a favored summer food is skunk cabbage leaves, but they also eat blueberry leaves and fruits and other things. On local wetlands, we have found evidence that they dig up the underground parts of silverweed, and in winter, we see them grubbing up the underground parts of sedges. We have sometimes found scats filled with poorly digested moss, which seemed unusual. The digestive system of these geese is not highly efficient, despite a good gizzard and a substantial microbial flora in the caecum and intestines, so they have to eat a lot.

Based on aerial surveys, the population of Vancouvers in Southeast is estimated to be about twenty thousand or a little more. It appears to be fairly stable, perhaps partly because it is not subject to excessive hunting pressure; historically, other populations in Alaska have crashed because they have been overharvested (in the Yukon-Kuskokwim area) or devastated by introduced foxes (on the Aleutians).

Thanks to Debbie Groves, US Fish and Wildlife Service, who provided several useful references.

December sightings

a hungry eagle, an unlucky goose, and an uncommon owl

Geese and ducks often fly from the wetlands to Auke Lake, as long as some open water remains there. These flights are especially noticeable during the hunting season, when the wetlands are dangerous for waterfowl. It’s called a ‘game refuge’, so during the hunting season, the wetlands are not much of a refuge but just a place to go to get shot. When hunters are active on the wetlands, Auke Lake offers a comparatively safe haven during the days, and the waterfowl return to the wetlands at night, to feed in the dark as best they can.

But Auke Lake is not totally safe. On a recent walk near the lake, on the broad, smooth trail completed a couple of years ago, we saw that safety had come to an end for one goose. We had missed the actual strike, but there on the ice was an eagle, happily (one supposes) tossing feathers aside and nipping small red chunks from its still-living prey. The goose flapped its wings occasionally, but to no avail, and before long, it was all over for the goose.

The eagle continued its lunch, surprisingly unmolested by ravens or magpies. Another eagle swooped in and was told off in no uncertain terms by the owner of the carcass. A second interloper was chased over the ice for some distance before giving up. Lunch was finished in peace.

Other sightings were less dramatic. Up along Fish Creek, as we were sampling aquatic insects, a friend watched a winter wren that was not doing its normal flitting through brush piles and stumps. Instead, this one was out in the open at the edge of the creek. It took one tiny item from the water surface and then probed the gravels for a few other morsels. More like a dipper than a typical wren.

A northern hawk owl has been seen in the Brotherhood Bridge area. Hawk owls are visual hunters, typically foraging during the day. A bird of boreal forests, it also hunts along forest edges. It is customarily a sit-and-wait hunter, perching quietly on a branch or snag while scanning the area around the perch, then changing to a new perch. They can also hover for short periods, and sometimes, like the forest hawks, they wing rapidly among the trees, to startle potential prey into revealing themselves. Hawk owls feed primarily on small mammals and birds, but they can take prey as large as ducks and grouse—two or three times their own body size. Although they can spot prey from hundreds of yards away, the usual strike distance is less than 50 yards. They are reported to have better hunting success when snow does not cover the ground.

n-hawk-owl-sue
Northern hawk owl. Photo by Sue Oliphant

Hawk owls, like other owls, catch prey with their feet, and often carry them to a plucking post. There the owl rips off feathers, tails, feet, or other unwanted but easily removed parts, and swallows the prey whole. Later, the undigestible bits are regurgitated in a pellet. Hawk owls, averaging about eleven ounces (but females are bigger than males) and perhaps fourteen or fifteen inches long (including a long tail), can swallow two whole mice in quick succession.

Northern hawk owls nest in Southeast, but rarely. They are more common in the Interior. However, if prey becomes scarce there, they move south some distance, until they find better hunting. Hawk owls can store prey in snow, tree holes, stumps, or thick branches; one observer noted storage of twenty prey items in three hours. Prey is also stockpiled at the edge of nests.

They commonly nest in tree cavities or sometimes on snags, and there can be fierce competition with squirrels, kestrels, or certain ducks that also use such nesting sites. Male hawk owls show several potential nest holes to their mates, and the female then chooses one of them. She lays an unusually large clutch of eggs (for an owl), averaging seven eggs per nest but sometimes as many as thirteen. Incubation lasts just over four weeks and begins well before the last egg is laid, so the chicks hatch asynchronously and there are chicks of all sizes in the nest. They are fed frequently and grow very fast. They are reported to leave the nest when they are about three weeks old, long before they are able to fly, and the parents feed them on the ground or wherever they find them. Presumably, the youngest and smallest chicks die of neglect and starvation if food is scarce, as is typical of many other birds.

Visiting Gustavus

observations on geese, raptors, otters, and the effects of moose browse

One of the first things I noticed was a roadside muskeg in which the shore pines were in sorry shape, with many brown needles. Upon inquiry, I was told that these pines are infected by a fungus that causes needle blight. The fungus kills off mostly the older needles, so an affected pine has only small tufts of newer needles near the branch ends. A serious level of infection can kill the tree. Cool, wet weather favors the production of spores, which are spread by wind or rain-splash, and the spread of this disease. And that’s the sort of weather that has prevailed this spring, it seems.

A flock of several hundred white-fronted geese loafed peacefully in someone’s back yard, while an off-shoot group foraged nervously in a nearby field. These birds were on their way to the nesting ground on the tundra up north. They were enjoying an important way-station on their journey, where they can feed and rest.

A pair of Canada geese seemed to own a piece of pasture, apparently unruffled by grazing horses. But they reacted sharply when a little flock of other geese came in to graze. The small group of new arrivals was a mixed lot—mostly white-fronts, a couple of Canadas, and a sole snow goose. The residents paced back and forth, talking at the unwelcome visitors, who went right on grazing but did not venture much farther into the pasture.

The great outwash plain created by melting glaciers supports numerous stands of willows, most of which have been severely browsed by moose, such that they seldom exceed three or four feet in height. ADF&G has a long-term study of moose ecology and the effects of moose browsing, focused on a set of exclosures that prevent moose access. The willows inside the exclosures look markedly different from those outside: the inside willows are much taller and produce more catkins. The paucity of catkins on the heavily browsed willows may have extended effects, well beyond the diminished reproductive capacity of the willows themselves. Willow catkins are an important source of food (pollen, nectar) for queen bumblebees, which mate in the fall and overwinter in small burrows. In spring, they need to feed so they can produce broods of workers. Bumblebees are important pollinators of blueberries, beach pea, lupine, and many other flowers. So the obvious question is: Does moose browsing significantly reduce the spring food of queen bees, thus reducing their ability to produce healthy broods, and thus impairing the pollination success of various flowers?

bull-moose-young-browsing-on-willows
Photo by Bob Armstrong

There may be other ripple effects of moose browsing. For example: Browsed willows produce fewer leaves and therefore less leaf litter below the shrubs. So we can ask if the reduced leaf litter affects the mosses, lichens, grasses, and herbs that constitute the ground cover. A lower number of leaves on the browsed shrubs should reduce their growth rates, because fewer leaves mean a reduced capacity to synthesize carbohydrates that provide energy. And one has to wonder if the cropped-off willows offer fewer nest sites and foraging surfaces for birds, leading to a lower density of birds than would occur in unbrowsed stands.

A male harrier coursed up and down the deeply incised channel of a tidally-influenced river that runs across the outwash plain; he was probably hoping to snag a shorebird or two. I heard snipe, high in the air, doing their flight display: as they swoop around, the rush of air over the spread-out tail feathers is modulated by the beating of the wings, producing a characteristic sound known as ‘winnowing’. Snipe winnow both on migration and on the nesting grounds, and most of these were probably still in migratory mode. I also think I heard a pygmy owl, tu-tu-tu-ing in the trees. A male robin carried a beakful of worms to his chicks, proving that the robins thought it was spring despite the raw, cold weather.

Another treat was the opportunity to watch three river otters exploring one of the inland ponds near Bartlett Cove. I suspect this was a family of a female with two of last year’s offspring, although there was not much difference in size. Otter families often stay together over a winter and into the next spring. These otters were well aware of our presence and kept bobbing up to peer at us. I was told that river otters are often seen as they travel considerable overland distances in Gustavus, visiting inland ponds (are there fish to be caught??) and returning to the ocean shores.