April

winter or spring?

The ice is just starting to melt on my home pond, so there is a little open water at both the inlet and the outlet. As soon as there were a few square yards of open water, a pair of mallards moved in. They rested on the edge of the ice, dabbled in the shallows, and gobbled up sunflower seeds spilled from the feeders that hang over the pond.

Then one day I noticed quite a kerfuffle out there. The female was hard to see, posed rather flat on the water. The male was very excited, vigorously bobbing his green head up and down, and splashily diving near the female several times. Quite a showy preamble! Then he was on her back, nipping the back of her neck, and they were doing the mating thing.

She will probably lay seven to ten eggs and incubate them for about four weeks. So, if she and her eggs are lucky enough to avoid predation, I may see ducklings on my pond in due course.

A stroll to Nugget Falls yielded the first purple mountain saxifrage of the season, blooming considerably in advance of others in the area. The flowers of this species are usually female, with receptive surfaces for pollen, before they become functionally male, with ripe pollen. So this plant had perhaps lost its chances for seed production, because the flowers clearly presented mature pollen. If a bee now happens to find it and remove pollen, it would be difficult to find another plant ready to receive that pollen—unless some other plants open their flowers very soon. Maybe a bee can fly to the west side of the lake, where this plant blooms on the rock peninsula. Maybe it doesn’t pay to be TOO eager! Research has shown that seed production in the species is commonly limited by insufficient pollen deposition.

purple-mountain-saxifrage-on-April-10-2013-at-Nugget-Falls

In the same area, where mountain goats have been foraging and resting for months, I finally saw a nanny with a kid, moving up the ridge into the brush. The kid was pressed close to mama’s side, so what I really saw was a white blur with eight legs (well, seven legs, actually, but you get the idea…).

Another stroll, on the wetlands, treated me to my first ruby-crowned kinglet song, one of my favorites. They’ve been here for a little while, but I hadn’t heard them for myself. Six swans on the river took off when they saw me move, even though I was still pretty far away and partly concealed. Canada geese were also quite nervous and left the meadows for the far side of the river. Even the ducks were uneasy and sailed slowly away downriver (mallards, goldeneyes, ringnecks, buffleheads, green-winged teal). Sadly, I missed the mountain bluebirds that had stopped there on their way north.

A more strenuous outing took us, on snowshoes, up one of the forested slopes at Eaglecrest. We gained a fair amount of elevation and looked down on the upper cross-country ski loop and Cropley Lake. We watched a ptarmigan snatch buds from blueberry twigs, marching calmly from one bush to another. The first clue to its presence was a line of very fresh tracks in the fluffy snow that lay atop the hard crust.

The greatest fun concerned a raven. First, we heard a lovely little melody coming from high in the hemlocks. It was repeated several times. The song was unlike that of any other songbird that I know. So we couldn’t identify it—until one little trill was followed by a brief squawk. Then a raven flew in, carrying a stick, disappeared briefly, and then flew back the way it came. Back and forth it went, with a rush of air in the wing feathers, each time bringing a stick. All the sticks were about the same size, maybe a foot long or so. After the bird had made several trips, I finally spotted where the sticks were going: high in a hemlock, in a snug spot next to the trunk, was a dark lump. The next two times the busy raven arrived, we could watch it work the sticks into the existing structure. This raven was still building the nest exterior, a bit behind the others that I’ve watched, which have been gathering and carrying dry grasses for nest lining.

Ravens are technically songbirds, along with sparrows and warblers and thrushes, although that comes as a surprise to many folks. On this day, ‘our’ raven earned its technical classification, with it short, sweet, melodic song.

Then, on a fine, blue-sky day, Parks and Rec sashayed, in shirt-sleeves, up to Spaulding Meadows. We didn’t even need snowshoes until we reached the upper meadow, because the trail was well packed. This trail is far easier to negotiate in winter than in summer, because the myriad mudholes are frozen and snow-covered. The upper meadows looked like the skiing would be wonderful, and the two skiers that started out with the rest of us plodders soon disappeared and were not seen again that day. Just before the top, we found some tracks that I think were made by a pine marten. We perched on a snowbank for lunch, shielded from a little breeze by a stand of trees, and thoroughly enjoyed a view of the sunlit peaks around the glacier.

Eating lichens

it helps to have four stomach compartments

mountain-goat-kid-2-eating-lichens-by-bob-armstrong
Photo by Bob Armstrong

Mountain goats appeared on the cliffs near Nugget Falls in February, as they often do. My occasional visits to the area have revealed two females and one juvenile, sometimes feeding on alder twigs and once I saw an adult engulf a whole conifer branch. They also nibbled on mosses and lichens close to the ground; we could see that one of their choices was the white foam (or snow) lichen (Stereocaulon).

Here in Southeast, deer, moose, and goats commonly eat lichens, especially in winter when there is no greenery. I’ve seen browse lines in the forest, where deer have munched all the hanging lichens (such as witch’s hair, Alectoria) up to a certain height. Up north, and across the Arctic, caribou and reindeer depend on lichens; in winter they dig away the snow to reach lichens on the ground.

These observations begged the question: What nutrition do lichens provide? Most lichens are low in protein (around two percent) but offer substantial amounts of carbohydrate. Some lichens contain cyanobacteria that fix nitrogen, and these have higher protein value, but they are reported to be less favored by some mammalian lichen-eaters. However, mountain goats are known to eat them. The white foam lichen that the goats by Nugget Falls were eating has about seven percent protein, which is not high, but better than many other species.

Goats, deer, moose, and caribou are herbivores with four-compartmented stomachs adapted to help break down the complex carbohydrates that compose the bulk of the lichens and summer herbage that they eat. A well-developed bacterial flora turns the big carbohydrate molecules into simple sugars that can be absorbed in the intestines. Regional differences in the available species of lichens are accompanied by regional differences in the bacterial flora adapted to these dietary differences. A well-adapted bacterial flora can increase digestibility several-fold.

A now-classic story is that of the introduction of reindeer to St. Matthew Island in the Bering Sea. The Coast Guard had a station there and in 1944 brought in twenty-nine reindeer for an emergency food supply. But the Coast Guard departed a few years later, leaving the reindeer. By 1963 the herd had increased to about six thousand animals. But the population crashed, during the next two years, to just forty-two animals. They had eaten up most of the lichens, and an extremely severe winter, with deep snow, high winds, and low temperatures, quickly finished off thousands of them. By the 1980s, not one was left.

Other mammals eat lichens too. In some areas, horsehair lichen (Bryoria), which is often common on tree trunks and branches, along with certain other arboreal lichens, comprised eighty or ninety percent of the diet of flying squirrels. Red-backed voles eat horsehair lichen and reindeer lichens. These rodents do not have the complex stomachs found in deer and goats, but they must have a good community of bacterial to help digest all the lichen that they eat.

Hordes of invertebrates eat lichen too. There are mites, springtails, small insects, snails and slugs that include lichens in their diets. Sometimes one can see the distinctive scrape marks made by snails or slugs that rasped off the surface of flat, leafy lichens.

Humans eat lichens too, but they often boil it in several waters to remove bitter flavors and cook the lichens in various other ways. These treatments probably improve digestibility as well as flavor.

Lichens are known to accumulate pollutants from the air; in fact, some are useful indicators of air pollution because they sicken and die off in filthy air. They also accumulate radioactive fallout. Even low levels of air-borne pollutants and fallout build up in these lichens, and therefore the animals that eat lichens may regularly accumulate lots of pollutants and radioactivity in their bodies. And then the predators of the lichen-eaters get poisoned too: The wolves and humans that eat deer and caribou, the eagles and ravens that scavenge the carcasses, the owls that hunt rodents, the birds that glean small insects…all of them can accumulate damaging material from polluted and radioactive lichens. In some cases, the buildup of dangerous stuff may be sufficient to change their behavior, impair disease resistance, or diminish their ability to reproduce.