Northern Waterthrush
Seiurus noveboracensis

Migratory Status: Neotropical migrant

PIF Population Estimate: 13 000 000

Percent of western hemisphere population breeding in boreal forest: 56%

BAM Effective Detection Radius (m) : 101.91

PIF Maximum Detection Distance (m) : 200

Canadian BBS Population trend: -0.7 n.s. (-1.7 to 0.3)

Life History

The Northern Waterthrush is a large terrestrial warbler species that breeds commonly in boreal wetlands across Canada. Its breeding range extends from northwestern Alaska east across the boreal forest into Newfoundland and Labrador, and south into the northern United States. This species overwinters in mangrove forests, with its winter range extending from southern Florida, south through Mexico, the Greater and Lesser Antilles, Central America, and into Columbia, Venezuela, Brazil, and Ecuador in South America. Unlike most migratory neotropical songbirds, the Northern Waterthrush holds and defends a territory not only while breeding, but also on its wintering grounds.

Males and females are monomorphic in appearance, with a white (or yellow) eyebrow and a uniformly olive-brown back that contrasts against a heavily streaked white (or yellow) underside. Three subspecies (Seiurus noveboracensis noveboracensis, S. n. notabilis, and S. n. limnaeus), are currently recognized based on geographic variation in colour and body measurements (i.e., morphology).

In the Great Lakes Region the breeding range of the Northern Waterthrush overlaps with the Louisiana Waterthrush (Seiurus motacilla), its closest relative. These species are similar in appearance but with subtle differences, and utilize different foraging habitat types. The Northern Waterthrush prefers slow-moving water systems, while the Louisiana Waterthrush prefers fast-moving water systems. Both species characteristically bob their tails in a down-up-down motion when foraging and walking, which is another diagnostic tool for identifying these birds in the wild.

Reference(s)

Eaton, S. W. 1995. Northern Waterthrush (Seiurus noveboracensis), The Birds of North America Online, . A. Poole, Ed. Ithaca: Cornell Laboratory of Ornithology; Retrieved from The Birds of North America Online database: http://bna.birds.cornell.edu/bna/species/182