Three-toed woodpeckers

On a nice June day I was traipsing along the Outer Point trail when I heard some loud chattering. As I got closer, I saw two women standing in the trail, gazing up at the source of all the noise. There was a hole in a small dead tree, maybe ten feet up, and the chatterer’s head poked out. A woodpecker, of course, but which one? The parents were very diligent and also very quick while making their food deliveries, but after several parental visits we were sure they were American three-toed woodpeckers. Oh good, this was a chance to watch a bird that is not very common around here, although they are widespread across North America, in the northern and montane conifer forests.

None of us had binoculars that day, so I went back the next day, better equipped, so I could more clearly see the chick in the nest doorway. It was big enough to fill the entire opening, and it seemed to stay there, with its head near the door all the time I watched. So I don’t know if it had siblings down in the nest behind it. Normally, there might be three or four chicks in a nest. Although it was possible that some chicks had already fledged, if so, they were already dispersed well away from the nest site; I was confident that the parents did not have other chicks close-by. The one in the nest opening chattered incessantly—and I do mean incessantly!—even when it rested its head on the doorway and closed its eyes. Its tune changed when a parent arrived, or came into view nearby, with a load of food. Then the call notes got louder and slightly farther apart. But the regular clamor resumed as soon as the food delivery was accomplished. An insatiable offspring!

The very next day I went back again, with some special international guests, for the chance of seeing a new (for them) bird species. The huge chick was still in the nest, calling and calling, but now with a new little whirr in its repertoire. We all waited for an hour, and then I waited for another hour, but no parent birds came. Disappointing! It was very different from the previous day, when the parent birds delivered little tidbits every ten minutes or so. (The tidbits were really small, and quickly delivered. Very different from another nest I later observed, at which the large loads brought by both parents gave the chicks several ‘bites’.) Was this abandonment, or part of a weaning process, or….?

Photo by Bob Armstrong

The next day, the chick slept in the doorway, occasionally making rather soft calls. Two days later, the doorway was empty. I hope the chick fledged and is now following its parents around, begging and starting to learn how to flake off scales of bark.

Both parents usually participate in all phases of nesting: excavating a cavity, incubating (at least both have brood patches), feeding nestlings and fledglings. Males have a yellow crown patch that females lack, but—oddly—chicks of both sexes have a yellow patch, which is eventually lost by females.

The parents had been unfazed by us standing in the trail, just a few feet away from the nest tree. Nor were they bothered by a dog, a small child and her father sitting right below the nest. They obviously persevered through the noisy process of recent trail repair in that area, which must have overlapped at least with the early part of the nesting cycle, perhaps through the approximately two weeks of incubation and the first part of the three-week nestling period. Amazing resilience!

Three-toed woodpeckers forage chiefly by scaling bark on dead and dying trees, using a sideways strike of the bill, and bark beetles are said to be a major food. But they also drill for wood-boring beetle larvae (though less often and less deeply than the related black-backed woodpeckers). Surprisingly, in spring and early summer, at least in some areas, they also make sap wells in bark and sip the sap, as sapsuckers do regularly (although they may not have the brushy tongue that sapsuckers use to lap up sap; I found no information on that).

By why do they (and the black-backed) have only three toes (pointed forward), when most other woodpeckers have four toes (three forward and one back)? It might have to do with how they pound on the tree trunk. To initiate the strike, they lift the whole body away from the tree, standing more or less on tiptoe with heels raised. It is thought that a fourth toe at the back of the heel might interfere with raising the heel as part of delivering the whole-body strike. In addition, the head drives forward. Ribs near the base of the neck are broader than usual, for extra muscle attachment, aiding the strike and stabilizing the neck. So they can deliver quite a wallop.

Ah, but doesn’t such a hard strike hurt their heads? Maybe not: certain muscles related to bill movement may absorb some of the shock and help spread the shock over a wide area.

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This and That

In early June, I went with a few friends to check out some muskegs at Eaglecrest. In addition to the common round-leaf sundew, we found some long-leaf sundews already making flower buds. Both of these diminutive species supplement their income by capturing hapless small insects on sticky hairs on their leaves and digesting their victim’s juices. There seem to be minor differences in their preferred habitats: longleafs are more likely to grow on soils less densely covered by mosses and other plants. For some reason, perhaps habitat availability in part, longleafs seem to be much less common than the other sundew.

Sundews are not our only insectivorous plants. Butterworts grow in the meadows on Douglas, for example, and in the subalpine meadows on Gold Ridge. Their leaves are sticky traps for insects. Bladderwort is a delicate, fragile aquatic plant sometimes found in muskeg ponds; it captures tiny aquatic creatures in ingenious little bladders with a narrow opening. The opening of each bladder is guarded by trigger hairs; when disturbed by a passing crustacean or insect, the triggers signal the bladder to open. The walls of the bladder are held inward under tension, but when triggered, the walls expand, and the lowered pressure inside the bladder sucks in the victim. Nifty!

While we were exploring the Eaglecrest muskegs, we also noticed that some of the shore pines bore tiny red rosettes near their growing tips, usually on the upper branches. What???? Not some other organism that has taken up residence there. I was sure I’d seen these bright rosettes before, but any knowledge of them seemed to have fallen through the ever-widening cracks in what used to be my memory. However, after a bit of discussion, we settled on the right answer—these are brand new seed cones! Other shore pines bore clusters of pollen-producing male cones, just at the right time to pollinate the new cones.

Photo by Kerry Howard

Reproduction in pines is a complex business that includes many seemingly strange delays. The new seed cones were initiated the previous fall but don’t emerge as rosettes until spring. Only the upper scales of the red rosettes bear fertile ovules. When the scales of the rosette open up, a drop of fluid appears near the ovule; this is called a pollination drop. It lasts two to four days, and then it is withdrawn, pulling in any pollen brought in by the wind. The rosette scales then enlarge and close; the receptive period is over. However, the pollen does not germinate immediately, and fertilization of ovules occurs about a year after pollination. Then the embryos develop over the following year, and the seed is filled with food for the seedling. However, pollen from another individual tree is more likely to result in viable, filled seeds than pollen from the same individual. Then the seed cone scales enlarge, and after two full years, the seed cone is mature and ready to shed its seeds.

So, if (and that’s a big ‘if’) a twig makes a cone or two every year, observers might see the red rosette at the tip, then a small cone or two where last year’s shoot tip was, and below that, a mature cone ready to shed seeds in fall. Older cones that have long since shed their seeds may still cling to the twig farther down.

Shore pine cones take two years to mature, but there are other kinds of pines in which cone development takes even longer, as much as six years! But why?? For comparison, seed cones in spruce and hemlock mature in the year they are pollinated. What ecological factors account for the great differences in the ‘strategies’ of cone maturation among all these related conifers?

A few days later, a beautiful brown spider, with gold stripes on its long abdomen, clung to the top of a beach-rye seed head. As I watched, it crept out into the space on the eight-inch journey to another seed head, seeming to walk on air. I could see that two of its legs were prodigiously long, far longer than the other six. Then it fussed about on the second seed head for a short while, moved down an inch or two, and slowly came back to the first seed head. Of course there must have been some silk strands in place, but I could not see them from any angle of view, they were so fine. The diligent spider then seemed to lay down some vertical strands across the existing horizontal ones, working on an invisible web. I would like to know how the first horizontal threads were laid down across that sizable gap. I don’t know her name, so I can’t look up anything about this lovely beastie.

The next week, I perched on a log in the sun, with a clump of beach pea on one side and a stand of lupine on the other. Several small worker bumblebees visited the lupines, erratically checking out a flower here or there on different inflorescences, zooming off a little way and then returning. Occasionally, one would open a flower, pressing down on the lower lip, but never stayed more than about one second. Was that time enough to sip some nectar or was this a sign that no reward was available? If nectar rewards were present, why were the visits so erratic?

 

What a contrast with the behavior of a big, fat queen bee, who was all business. She went straight to the beach peas and systematically visited every open or nearly open flower in the clump. Her behavior suggested to me that she was regularly rewarded for her visits—otherwise, why stay

On flowers

On a day of filtered sunlight alternating with rain showers, Parks and Rec hikers headed up the Dan Moller trail. Many of the boards on this trail are rotten, broken, unstable, or missing altogether, necessitating detours into the meadows, destroying vegetation. On the plus side, the flower show of bog rosemary made a pink, pointillist impressionistic picture, punctuated with the deeper pink of bog laurel and Jeffrey’s shooting star. Another plus was hearing the so-distinctive song (quick, three beers!) of the olive-sided flycatcher.

Other flower shows are on their way, too. Common shooting stars in Cowee Meadows made a bright pink blanket, soon to be overcome by the purple and blue of lupine and iris. Above the tram on Mt Roberts, cream-colored narcissus-flowered anemones dominated the subalpine zone but did not entirely obscure the little pink wedge-leaf primroses (‘pixie-eyes’), yellow sibbaldias and avens, and three kinds of violets.

Although some gardeners may complain about the rain, if it interferes with their planting activities, I was pleased indeed that the rains came. My home pond is almost full again and maybe some streams are recovering a little from their sorry, almost-dry condition. However, Dredge Creek and its ponds are still extremely low. Without a steady supply of snow-melt from the mountains (where there was little snow this year), the salmon streams depend on rain to fill their channels and make fish passage possible. And without salmon, the bears will be very hungry and no doubt cranky.

A few days ago, a friend and I were working in the Dredge Lake area, checking the protective cages that guard a few of the trailside cottonwoods from beaver chewing. We were enjoying the songs of northern water thrushes and warbling vireos as we walked along the old dike near Moose Lake, when we heard a sharp Snap!—a branch breaking. Then another Snap! Hmmm—Somebody’s out there…but it wasn’t the thrashing of branches that an annoyed bear can make. Then a third Snap! OK, let’s go look. Peering up into the canopy, we spotted a large black lump wedged against the trunk, very high in a big cottonwood tree. Snap! And down came a branch. Aha! The bear is harvesting cottonwood seed pods. Some years ago, we often observed such behavior near the visitor center: bears way up in the trees, eating first the catkins on the male trees and then the pods from the female trees. Some of the trees in that area still show signs of that activity—broken branch stubs not yet concealed by new growth. I was glad to see this bear in action that day; there have been fewer observations of such activity near the visitor center in recent years.

Mid-May field notes

Pollen storms erupted from the hillsides as spruce trees matured their reddish male cones and shed their pollen. Smoke-like clouds of yellow rose from one hillside after another. Major pollen storms don’t happen every year, and I’d like to know what triggers them. Some of that pollen landed on female cones and fertilized seeds, so maybe there will also be a big spruce cone crop later this year.

Much of the pollen was wasted (from the trees’ point of view), landing all over houses, cars, gardens, and everything else. My deck turned yellow, and cars acquired a dusty yellow tinge; leaves were coated with pollen. Pollen that washed up in the intertidal zone covered mussel beds with a yellow blanket. The film of pollen on the surface of my home pond didn’t seem to deter the visiting mallards, and they made gorgeous paisley patterns as they swam about, making paths in the pollen film.

–Cowee Meadows: a spectacular show of blooming shooting stars! A week earlier, there were lots of them, with more in bud, but now there was a sea of pink flowers, all waiting for bees to visit. Irises and chocolate lilies were still in bud. The first small dragonflies were on the wing, and a damselfly too.

–Indian Point: a walk at a not-very-low tide discovered no hermit crabs but lots of five-armed sea stars in a variety of colors. I picked up a huge whelk shell, with a vague thought of taking it home. But when I looked inside, I saw a tiny lined chiton safely ensconced well inside the opening. So I put the shell and its inhabitant back where I found them. A group of harbor porpoises was busily fishing close to shore. They dashed back and forth, sometimes coming right out of the water, sometimes briefly disappearing altogether. ‘Twas a treat to see them so close.

–Cropley Lake: The lake was still mostly ice-covered! I watched two small insects in a tiny muskeg pool for over half an hour. One that looked like a fly grabbed the other’s abdomen, with much flailing about. Gradually, the fly’s head seemed to move up the other’s body, which slowly got shorter and shorter, although the apparent victim still waved and curled its wee antennae. I lacked the patience to await the final outcome.

–Spaulding Trail meadow: I watched a jay forage, hopping over the sphagnum, flying up into a pine to scout its next move, then over the mosses again. As I watched, a moth landed on a stem in front of me. Its folded wings were white, marked with strong black lines. I think this was a wood tiger moth, a species that ranges over much of the northern hemisphere.

Adults of this species do not eat at all; the caterpillars have a varied diet of herbaceous plants. Composition of the caterpillar’s diet affects the adult moth’s ability to resist pathogens and parasites. Chemical defenses secreted by glands in thorax and abdomen of adults also derive from the larval diet; these deter predatory attacks by ants and birds. The striking colors on the wings give potential predators (birds, at least) an advance warning that the moth is likely to taste terrible.

The wings of wood tiger moths are quite variable in pattern and color. Females have some red or orange on the hind wings, visible only when the wings are spread. The hind wings of males are either white or yellow. Research has shown that yellow-winged males are less likely to fall prey to birds but have lower mating success than white-winged males. Thus, each male form has a different advantage, and both forms are maintained in the population.

My visitor was a white-winged male. He crawled off the stem, up a sleeve to a shoulder seam, jumped off and dropped suddenly down into the vegetation, where he seemed to disappear. This is another defense move: the sudden drop followed by lack of motion, with the legs pulled in, makes it hard for a predator to track.

–Near my home pond, a red squirrel is often active, peeling spruce cones while sitting on a stubby dead spruce branch, or scolding some intruder. One day I watched it run casually out over the pond on a sawed-off alder branch, jump (without hesitation) into the pond, and swim a couple of yards to shore. This seemed to be a familiar short-cut, a nice way to save a long scamper. Don’t tell me (though someone once did) that squirrels can’t swim!

As I write this, a large, glossy, roly-poly bear is foraging on horsetail in front of my house. He is attended by a horde of mosquitoes, which don’t bother him much. Every so often he looks around, probably in response to a noise somewhere; he stands up and is more watchful occasionally, I think in response to a car on the road up the hill. The mallards on the pond and the juncos in the grass are unperturbed by his presence. This fellow is really intent on eating; in good spots he just lies down and eats every horsetail in sight. After almost an hour, he wandered off toward the campground.

A bit later, I looked out my window, and there he was again, submerged up to the top of his head, having a cool-off in the middle of my pond! What fun! He slowly ambled over to shore, climbed up to drip-dry and have a second lunch of horsetail, and then mosey onward.