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By Marie S. Harris
Geographic Range
In the breeding season, the Northern Waterthrush is found in a belt stretching from north central Alaska, east across all of the Canadian provinces. In the winter season, the species is found in the tropical mangroves of Central and South America.
Biogeographic Regions:
nearctic 
(native ); neotropical (native ).
Habitat
The Northern Waterthrush prefers cool, dark, wooded swamps, thickets of bogs, margins of northern lakes, and willow and alder bordered rivers. During the spring and fall migration, the bird can be found in thick cover along streams, in marshes, and by stagnant pools.
Terrestrial Biomes:
forest ; rainforest .
Aquatic Biomes:
lakes and ponds; rivers and streams.
Physical Description
The Northern Waterthrush is a large, ground walking warbler with a brown back and a white or yellowish streaked breast. The breast, sides, and flanks are streaked with a dark olive or black. There is an olive-colored triangular spot in the front of the eye and a crescent shaped mark on the lower eyelid. The throat is also covered with small triangular marks.
Some key physical features:
endothermic ; bilateral symmetry .
Reproduction
Pair bonding begins immediately after the female arrives on the breeding site. Males perch in trees that are standing near water while females are below usually feeding along the edge of the water. Males vibrate their wings and raise their crown feathers and sing. The female may answer with a chink. The pair bond is broken shortly after successful fledging. The male selects the general area of the nesting site, but the female chooses the actual nest site. Nests are usually in the cavity of a root system of wind-blown trees in a wooded swamp, on the side of a fern clump or under cover along the banks of a lake or a river. There is typically covering above the nest and an opening to one side. The exterior of the nest is mainly moss and liverwort gametophytes. The interior of the nest cup is constructed with grass stems, twigs, or pine needles, and then lined with the hair of deer, caribou, cow, and rabbit. Average clutch is composed of four white ovate eggs spotted with browns and greys. The female is solely responsible for incubation, which lasts 12 days. Both parents, however, share feeding responsibilities. After four to five weeks the chicks begin feeding themselves.
Key reproductive features:
iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous .
Behavior
The Northern Waterthrush is solitary before pair formation, then forms family groups after the young depart from the nest. The bird is an annual migrant to the West Indies and Central and South America. Migrations are made in loosely associated flocks that fly at night. The bird is seldom agressive towards other species; however, it has a strong reaction to the song of the Kirtland's Warbler.
Key behaviors:
flies; motile .
Food Habits
During the breeding season, the basic diet consists of larval and adult insects, spiders, and snails. After leaf emergence in the spring, the bird feeds on primarily on butterfly larvae. On the winter grounds, the bird consumes a greater variety of food, adding minnows and decapod crustaceans to its diet. The Northern Waterthrush forages alone using such tactics as twig gleaning, flycatching, hovering, chasing, and a lot of pecking. Microhabitats for foraging include water, ground, foilage, and air. Before leaf emergence, the Waterthrush typically spends about 75% of the time feeding in water, alternating between wading and walking along logs, on branches, and the water's edge.
Economic Importance for Humans: Negative
--
Economic Importance for Humans: Positive
Feed on insects that are regarded as pests to humans.
Conservation Status
IUCN Red List: [link]:
Least Concern.
US Migratory Bird Act: [link]:
Protected.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
State of Michigan List: [link]:
No special status.
Degradation of habitat and pesticides are the biggest threats facing the species. Northern Waterthrush populations, however, have managed to remain stable despite these threats. Drainage of swamps for agriculture and wetland development into ponds or lakes may reduce breeding habitat. Pesticides are also affecting the Northern Waterthrush. Aerial spraying for the spruce budworm can kill the birds directly or reduce the biomass of their prey.
Other Comments
Most bird watchers only see the Northern Waterthrush in backyards, city parks, and wet places when the bird is en route to the tropical mangroves of Central and South America
For More Information
Find Seiurus noveboracensis information at
Contributors
Marie S. Harris (author), University of Michigan.
