Mid-May field notes

pollen storms, a beautiful moth, and a backyard bear encounter

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.

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