What do you mean it’s not a Thrush?
by Gail Cleveland
Ornithologist E. H. Forbush’s observation about the Northern Waterthrush, made more than half a century ago, still applies: “It is a large wood-warbler disguised as a thrush and exhibiting an extreme fondness for water,” according to the Boreal Songbird Initiative.
The Northern Waterthrush is predominantly brown with brown streaking on its breast and a narrow pale eyebrow. Because of the thrush in its name and the similar coloration to our Hermit and Swainson’s Thrush, it is easy to assume that it is a member of the Thrush (Turdidae) family rather than a New World Wood-Warbler.
We tend to think of warblers as small, colorful birds that inhabit bushes and trees and are difficult to see. There are, in fact, three warblers that are brown with stripes on their breasts: Northern Waterthrush, Louisiana Waterthrush and the Ovenbird. The Ovenbird is a rare sighting in our area, while the Northern Waterthrush is quite common along streams, bogs and lakes. The Louisiana Waterthrush, very similar in appearance, makes the eastern and southern United States its breeding grounds.
These three brown birds of the wood-warbler family are considered terrestrial, whereas most of the other wood-warblers are considered arboreal. The ground-dwelling Northern Waterthrush gets its food below the forest canopy near the water’s edge, eating both aquatic and terrestrial insects and invertebrates. It also walks rather than hops as most warblers do.
Most North American wood-warblers have separate plumages for the male and female. In order to attract a female, the male often has bright, colorful plumage. Like wood-warblers of Central and South America that do not migrate, the male and female Northern Waterthrushes have very similar plumage.
They nest on the ground creating a cup of moss and leaves, lined with fine plant stems, rootlets, hair, and moss. Finding a Northern Waterthrush nest is not easy as it is often placed in a small hollow or cavity under a fallen log.
The female lays four or five eggs. Because of the hazards of migrating to Central America and northern South America each fall and returning in the spring, the Northern Waterthrush, along with other migrating wood-warblers, has larger clutches of eggs than warblers that do not migrate.
The Northern in its name comes from the fact that breeding takes place in much of Canada and Alaska. It is estimated that 56% of the world population breed in Canada. Breeding dips down into parts of the northeastern U.S., but other than Alaska, the only breeding grounds in the Western United States are western Montana and northern Idaho. So it is a target species for our area.
Because of the brown plumage of male and female as well as the tendency to be on the ground or skulking in the middle of a bush or tree, it is difficult to see a Northern Waterthrush. However, the loud, ringing song of the male will help get a glimpse. During breeding season, the male will sing from the tops of trees and tall brush in its wet environment, outdoing other warblers in loudness, if not beauty. Sibley describes the song as “a series of loud, emphatic, chirping notes, loosely paired or tripled and generally falling in pitch and accelerating.”
Two locations in our area that have consistently had singing Northern Waterthrushes in June are at the end of Whitefish Lake where Lazy Creek goes into the lake and at the Tally Lake Campground during Warbler Weekend, this year June 15-17.
Every year, I always look forward to the return of the elusive, but distinctive, warbler that looks like a thrush, singing his loud and clear streamside song, hoping to attract a mate