Saltmarsh sparrow
Saltmarsh sparrow
One of my favorite haunts at any season of the year, Weskeag Marsh, shifts its summer appearance and mood in October as the bright foliage reflections of roadside pools fade and succumb to brisk fall winds. The bulk of the marsh’s terrain is comprised of salt-tolerant plants and grasses that play essential roles in the lives of birds. And the nutrient-rich pools and salt pannes are of equal importance to bird life. As such, Weskeag is designated as one of Maine’s 22 Important Bird Areas.

How does Weskeag’s system of plants support birds and other wildlife? Several species of Spartina cordgrasses dominate the ground cover of the marsh. These grasses can tolerate daily fluctuations in salinity levels and water depths during tidal cycles. Today’s existing pattern of dikes and trenches was established to manage hay production that was harvested there in the past century. The hay was used mainly as bedding and feed for livestock and mulch, and some may recall the remnants of wooden straddles built to elevate the harvested hay above the tide levels.

Growing 3 to 6 feet tall, cordgrasses also play an integral role in the estuary’s food web. The base of the web begins with tiny insects that are consumed by multitudes of spiders that, in turn, become food for birds. Bounties of insects such as crickets, grasshoppers, moths and butterflies contribute to Nature’s food stocks as well.

Two species of marine sparrows rely on these specialized habitats for nesting locations and food alike. Nelson’s sharp-tailed sparrows and saltmarsh sparrows build ground nests lined with fine grasses. Of the two species, Nelson’s sparrow is the far more common in these parts, since Weskeag may be the northernmost breeding outpost for the now- endangered saltmarsh sparrows. Future projections for the saltmarsh species are dim as gradually heightening tides reduce their suitable habitat.

Timing of nesting and egg-laying activities is crucial to breeding success, since monthly flood tides may inundate nests with seawater. If not totally swept away, the eggs of the Nelson’s can tolerate brief water soakings and will actually float within the nest walls. Once hatched, however, the hatchlings must occasionally climb stalks of grass to remain dry and viable throughout the highest tides. In late summer and fall, these sparrows feed on the lush seed heads of the cordgrasses.

Each fall, you may notice brilliant patches of crimson plants encircling the marsh pools. This is Salicornia, also known as glasswort. A smooth, fleshy green succulent by summer, these small-leafed plants are supremely adapted to saline environments. At 4 to 20 inches tall, glassworts owe their short stature to expending so much energy excreting salt and drawing water into their roots that they don’t grow very large. The ashes of burnt glassworts contain large quantities of potash and were formerly used in glassmaking.

Like most weeds, wildflowers and vegetables, glasswort is an annual plant that completes its life cycle in a single growing season. The resulting seeds and stems become valuable food sources for foraging ducks and geese.

The Weskeag pools are the other part of its magical equation of habitats. By late fall, most tundra-nesting shorebirds have passed south, leaving behind contingents of migrating waterfowl. The spotlight then focuses on lingering greater and lesser yellowlegs and a few unusual shorebirds, such as a recent Wilson’s phalarope. Found mainly in the marshes of the Great Plains and intermountain West, the phalarope’s unique behavior often gives it away. This species spins rapidly in chest-deep water, creating whirlpools that stir up invertebrates. The bird then uses its needle-like bill to snatch its prey. Eventually, the wayward Weskeag phalarope will likely winter in Andes lakes of South America.