Diverse musings

At the mouth of Cowee Creek, sometime in mid-June, we’d found a vigilant pair of black oystercatchers, presumably with a nest nearby. A couple of weeks later, a small group of hikers stopped at the same spot and quickly noted that the adult oystercatchers were tending two tiny, downy chicks. The chicks had hatched quite recently; their legs and especially their bills were still very short (it would be impossible to fit an adult-size bill inside an egg). One adult guarded them closely while the other made short forays down the beach for food.

Oystercatcher chick. Photo by Bob Armstrong

Black oystercatchers are beach-nesters; both male and female construct the nest, which is usually made of rock and shell fragments. There may be one to three eggs per clutch, incubated for about four weeks by both parents. Eggs are reported to be tolerant of flooding by high tides. The chicks can walk and swim well three days after hatching; after about five days, they start to peck at possible food items. Very young chicks are fed mostly by the male, while the female broods or guards them. Later, when chicks can follow adults to feeding sites, the female takes a more active role in feeding them. Young ones may begin to forage for themselves at about ten days, but they are just learning, taking fewer and poorer items than the adults. They gain weight quickly, but elongation of legs and bills takes longer. Even at seven weeks, chicks get much of their food from the parents, mostly marine molluscs, the large ones cut up into conveniently small pieces. They can fly, then, but in general they are not fully skilled at foraging until they are about three years old. Human disturbance can lead to prolonged incubation and fledgling times.

The trail down to Cowee Meadow provided a nice surprise—a small, yellowish-pink, peculiar-looking plant with no green color at all. This plant is called pinesap, and we don’t see it very often. Without green pigments, it is not capable of photosynthesis and making its own nutrition. It is indirectly parasitic, tapping into the mutualistic mycorrhizal fungi that connect many green plants and carry nutrients from one to another. Connections to those nutrient-transporting fungi turn out to be essential for growth and flowering, and even seed germination of pinesap. The plant is subterranean except for the inflorescence, which pushes its way up above ground. The flowers contain nectar, and bumblebees are thought to be the main pollinators (although there may be some self-pollination too). At first, the flowers are pendant, but they tilt upward when the seed capsule is mature, thus facilitating seed dispersal.

Pinesap

By the end of June, the herbaceous vegetation in many meadows was decorated with the foam ‘houses’ of spittlebugs. Adult spittlebugs (a.k.a. froghoppers) can fly as well as hop, and they forage by sucking sap from the fluid-conducting tissues of plants. Stealing sap from plants can reduce the health and reproductive output of the plant, so gardeners and farmers don’t like spittlebugs. The bugs are also known to transmit certain diseases from plant to plant.

Spittlebug sign on fireweed

There are many species of spittlebug; the best-studied species lays eggs in plant tissues in late summer and fall; the overwintering eggs hatch in spring. The larvae (called nymphs) are sap-suckers too. They disperse from the hatching site, and once they get to a good feeding spot, they tend to stay put, molting several times as they grow inside that foam ‘house’. They produce the foam by mixing air and excess fluid from the gut with secretions (from the end of the abdomen) that stabilize the bubbles. The foam helps protect them from predators and parasites, perhaps various micro-organisms, temperature extremes, and desiccation. Sometimes several nymphs share a foam ‘house’.

Sap is not very nutritious, but spittlebugs (and many other sap-feeding insects) have help: inside certain abdominal cells are very specialized symbiotic bacteria that provide amino acids and vitamins that are used by the host insect for growth and maintenance. These helpful bacteria are apparently passed from mothers to offspring.

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Cowee Meadows observations

A splendid, sunny day at the end of May called for a visit to the flowery meadows on the Pt. Bridget trail. The day started off well—in the first muskeg near the trailhead, we saw flowers of eight species. As a bonus, “Quick, three beers!” sounded repeatedly from the edge of the muskeg—my first olive-sided flycatcher of the year.

Bracken fern was still unfolding along the trail into the forest and a few more flowers there were added to the list. A Pacific wren sang and a sapsucker called from a dead tree. Small white butterflies made courtship pursuits and a few tiny blue butterflies flitted by. The skunk cabbages were fading, but many of the sturdy inflorescences entertained a variety of small flies and beetles; the beetles are thought to be the main pollinators of skunk cabbages, but perhaps the flies can do the job too.

Emerging into the main lowland meadows, we were greeted by a wide expanse of bright yellow, chiefly buttercups in full bloom, with some tall blue lupines adding a bit of micro-topography. Below that cheerful canopy was an understory of pinky-purple shooting stars, and in certain places there was an under-understory of white strawberry flowers. It would be a while before the irises bloom; as expected, the buds were still small and safely enfolded in the vertical leaves. Wilson’s warblers sang along the edge of the meadows and savannah sparrows popped up out of the meadow greenery briefly, before diving back into cover.

Dawdling along, looking at flowers and bugs, we finally reached the estuary of Cowee Creek and settled onto a log at the very upper edge of the beach for a picnic. There we were greeted by strident calls and a black bird with a long red bill (and oddly pale legs) marched toward us while his mate lingered down by the water. I hadn’t been scolded by an oystercatcher for ages, so this was a welcome sound. This fellow walked up from the water-side, over a stretch of cobbles, until he was about thirty feet from our log. There he walked back and forth, parallel to the upper edge of the beach but below the highest tide line, as if patrolling a boundary. When we showed no signs of further encroachment, he settled down on a rock to watch for many minutes. He took time off to chase a raven upstream but came back to his guard duty. As we packed up to leave, he ambled down to his mate by the water. They will nest just above the high tide line, laying eggs in a shallow cup of sand.

Photo by Kerry Howard

Meanwhile, four female mergansers floated on the big creek, causing me to wonder if they were not nesting this year. A kingfisher hovered for a long time over a side channel, then dove and flew downstream out of sight, so its hunting success was unrecorded.

There are several large stands of sweetgale out in the meadows. This aromatic shrub has separate sexes, distinguishable by the flowering spikes: female spikes are smaller and bear a red tuft on the tip. As we’ve observed on previous trips out here, female individuals seem to be much rarer than males. But why??

By the time we got back to the car, we’d tallied over thirty species of flowers. Not bad for a partial tour of those big meadows. I was pleased to see small flies of several types visiting some of these flowers, along with a few small bees. Bumblebees were scarce, but a few zoomed around and one landed on a lupine. This activity was a big contrast to a recent walk up the Crow Hill trail, on an equally nice day, when not a single flower had an insect visit.

The main trail has been greatly improved by the trail crews, and it looks like they intend to deal with a few more spots. No-see’ums and mosquitos were all too active and will become more so…

Loons, baby birds, and springtails

The East Arm of Glacier Bay is a wonder-world of gerrymandered geology. Rock walls are made of obviously different materials, all contorted into swirls and folds and cross-veins. The pebbles on the beaches could keep a rock hound happy for hours. So many stories in stone! Oh, if only we’d had a geologist with us.

We knew a little more in a biological way, and there were lots of biological observations of interest.

Red-throated loons called un-melodiously as they flew overhead, and family parties loudly yakked and squawked to each other. They nest on lakeshores and fly to nearby saltwater to forage. My best memory of them is our nest-searching effort, some years ago. My crew and I saw a pair carrying fish over a huge sand ridge, so we knew there had to be chicks somewhere on the other side. Ever-so-quietly, we belly-crawled up the side of the ridge and peeked over. But those loons knew we were coming! They stood there glaring up at us and did not reveal the location of the chicks. Hmph. Outsmarted by loons!

As always, finding bones leads us into mental exercises. A small bird’s pectoral girdle required some re-assembly (and memory-dredging). A very large sternum with an inflated keel may have come from a swan. Part of a fish jaw held three rows of tooth sockets in graduated sizes, prompting the question of who had owned this jaw and how, exactly, was it used?

Perhaps the greatest fun was provided by baby birds and their parents on the beaches. We watched a very aerobatic male yellow-rumped warbler capturing insects for a fluffy, bob-tailed fledging that scuttled over the beach cobbles, trying to keep up with its father. One bewildered young warbler blundered into my shoulder as I sat watching the show. Another found itself in our ‘kitchen’ and perched on a bear barrel, briefly. We saw these woodland warbler families on many beaches, taking advantage of all the flying and crawling insects (We sure wished they would make a perceptible dent in the hordes of mosquitoes and blackflies and no-see-ums.)

Black oystercatchers were still incubating eggs on some beaches, but on others, chicks of various sizes scurried over the rocks or scrunched down, almost invisibly, beside boulders. Their parents were very busy, bringing shellfish and crabs to the insatiable youngsters. It seems that oystercatcher chicks need to be taught to peck at their food. We watched adults place a prey item in front of chicks and poke at it several times, before the chicks got the idea and pecked at it themselves. Every so often, the adults would fly off to join other oystercatcher pairs in screaming parties. A group of six or eight birds would fly back and forth just off-shore, yelling and hollering, for several minutes, and then each pair would go back to its own territory along the beach. Why do they do that?

A big puzzle came from observing billions of tiny springtails floating down the freshwater rivulets that often run across the beaches. They used their little forked spring-tails to jump off the water surface; they are so small that the surface tension of the water can serve as a launching platform. Hordes of these minute creatures floated and hopped down the little streams and congregated eventually at the edge of the cove. I imagine that they were still basically in fresh water, because that water is lighter than sea water and can form a layer on top of the salt water. But what was all this about? A mating swarm? Or were they driven out of their usual haunts by something? And what are their usual haunts, anyhow—does this kind of springtail live in the interstices of the beach gravels, or somewhere upstream? Many unknowns!

One night, some of us were awakened by growling and snarling, very close to some of the tents. This generated some excitement and alarm, until more experienced ears identified the growler as a river otter, displeased at the human occupation of its beach. The next day, an otter swam by, inspecting the camp from the water. No doubt it was pleased when we left!