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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Plants that aren’t green

Most of us think of plants as being green, at least in summer. The green comes from the pigment chlorophyll, which uses sunlight to knit carbon dioxide and water together, forming carbohydrates that the plant can metabolize. Lucky for us, oxygen is a by-product of the process. There are a few local plants, however, that don’t have chlorophyll, or at least very little, so they don’t do photosynthesis and have to obtain their energy elsewhere. Here are examples:

Northern ground cone. This interesting Beringian plant goes by the reverberating scientific name of Boschniakia rossica, named for a Russian botanist Boschniak and presumably someone named Ross. Such names reflect nothing about the plant itself, obviously, and only show who knew whom. That’s a shame, because this plant is rather weird and wonderful.

Northern ground cone got its common name because, to some people, the above-ground plant resembles a pine cone. It is common in certain places around here, mostly where there are alder trees. Lacking chlorophyll, it cannot synthesize carbohydrates for itself. Northern ground cone is entirely parasitic, getting its nutrition from other living plants, especially alders but also other species.

The brownish spike that emerges from the ground in summer is the inflorescence, bearing numerous small flowers. When mature, the spike produces huge numbers of tiny seeds.

The plant is reputed to have some medicinal value for humans (although, like many plant medicines, it has some toxic properties too), but part of my interest in it stems from observing that it seems to be a favored food item for bears. In the Dredge Lake area, for example, I often see wide swaths of ‘rototilling’, showing where bears have been foraging for northern ground cone. Bears seek out the underground base of the spike and generally leave behind the spike itself. The stem-bases are not notably rich in basic nutrients such as nitrogen, phosphorous, potassium, or calcium, and probably provide carbohydrates. When bears have been eating lots of ground cone, their scats look (to me) rather like mushy cracked-wheat porridge.

A fly enters the flower of a northern groundcone. Photo by Bob Armstrong

The tiny flowers are accessible to small insects, which are sometimes seen to visit, but it is apparently not known if they are pollinators. A different species of ground cone is reported to be self-pollinating, and a little fly sometimes attacks the flowers of that species. But the story for northern ground cone is yet to be discovered.

Pinesap. This is another strange plant that lacks chlorophyll. Pinesap (alternatively, Dutchman’s pipe) grows under conifer trees. It seems to be much rarer than ground cone in our area, as I have almost never seen it around here. It is sometimes said to be saprophytic, obtaining nutrients from decaying vegetation, but the reality is more complex. This plant and its close relatives are obligately dependent on mycorrhizal fungi whose underground filaments connect to the roots of nearby trees. The fungi draw nutrients from the host trees and delivery them to the pine sap plants. Thus, the pine saps are indirectly parasitic. Pine saps have yellowish or reddish stems, with yellowish or red-tinged flowers usually bent over to one side. When the fruits mature, however, they are upright on the stem. Bumblebees are reported to be the most important pollinators.

Certain local orchids are also saprophytic. We have two species of coral-root orchids, both of which are said to be saprophytic, but again the arrangement may be more complicated. In addition to needing mycorrhizal fungi for seed germination, these plants may, like the pine sap, actually obtain nutrition via their associated fungi that drain nutrients from nearby host plants. In addition, one coralroot orchid is said to have small amounts of chlorophyll and thus synthesize some of its own carbohydrates. Coralroots may be pollinated by small flies, such as dance flies, but probably also have the capacity for self-pollination.

Some June sightings

The Sheep Creek trail in spring and early summer is almost always good for hearing bird songs, but this day was hot (in Juneau, that means over 70 degrees F) and we were there late in the morning, well after the usual dawn chorus. So I was a bit surprised that the listening was still quite good. I heard several Swainson’s thrushes, which arrive from their wintering area well after the other songbirds. Fox sparrows and robins were singing, presumably starting second broods. A few kinds of warblers were sounding off here and there, and even ruby-crowned kinglets, who start their lively concerts in late March, still sang a little (albeit a trifle feebly).

We found two treats from the plant world. One was a healthy specimen of three-toothed saxifrage (Saxifraga tricuspidata) on a rock near the trail. This species is not common here, being mostly a species of the Interior. It has spotted petals, as does the related spotted saxifrage, which has small, rounded leaves (no teeth).

The other good find was a happy little stand of a parasitic plant called (among other names) pinesap. The taxonomy of this plant has changed, reflecting great confusion about its relationships. It might be called Monotropa hypopitys or Hypopitys monotropa; related to the wintergreens, it is now categorized in the blueberry family (Ericaceae). In any case, the plant is less confused than the taxonomists: it has no green tissue and is entirely dependent on its hosts for nutrition. Mycorrhizal fungi connect the parasite to conifer trees and transfer nutrients to the parasite. The flowers of pinesap are pendant until pollinated (self-pollinated or perhaps by bees?) but become erect when mature and ready to disperse seeds. These plants are reported to be yellowish if they flower in spring or summer, but reddish if they flower in fall. I have not seen this plant very often around here, but we did see another one this year, over on west Douglas.

Photo by Kerry Howard

A small excitement was stirred by a wasp nest adjacent to the trail, on the ground. We could see the paper wall of the nest through the torn vegetation. Something had already disturbed the colony, which was swarming over the trail as we went into the valley, and the swarm of unhappy wasps was still there two hours later, when we left. No casualties to passing humans, but that nest may not survive.

Gold Ridge never disappoints us: if we tire of looking for marmots or watching eagles catch the thermals to soar up the face of the ridge, there are some nice plants to inspect. I found a pair of frog orchids along the trail in mid-June, but by late June they were gone—simply finished or maybe trampled. More could be found by a good observer somewhat higher on the ridge. Butterworts, which catch insects on the sticky leaves, had flowered in the early part of June and by late June some of them were setting seed. The inky or glaucous gentian, with its unusual blue-green flowers was ready to bloom in late June.

Earlier in the season, we had thirty seconds of intense excitement: from over our shoulders came a prolonged, piercing scream and a dark falcon in hot pursuit of a songbird. The songbird dove into a thicket below us. The merlin circled ‘round and back up the ridge, hoping for better luck.

Near the glacier in late June, the dippers had raised one early brood of chicks, but sadly, showed no signs of raising a second brood, even though the pairs that nest at this site often do so, and there was plenty of time this year. Porcupines were busily shredding cottonwood leaves. The sockeye were not yet in and the bears were making themselves quite scarce. A few years ago, during several spring seasons, bears were commonly seen up in the cottonwood trees, feeding on the catkins and leaving lots of broken branches, but we have not seen much of that activity in recent springs. Quite puzzling!

We had fun keeping track of the robin that chose to nest under the raised walkway. How she tolerated the thousands of tramping feet overhead is a mystery. But she incubated four eggs; one hatched a day after the others, indicating that incubation had begun with the third egg. The female sat on her eggs for around twelve days. When they hatched, the male appeared, and both parents tended the chicks. In early July, the nestlings survived the rising waters of the jökulhlaup by a few inches and fledged after about two weeks in the nest.