Merlin

Northern Waterthrush Life History

Habitat

Habitat Forests

Northern Waterthrushes frequent wet habitats with dense ground cover. Across their large range, they use wooded swamps, bogs, and thickets bordering all manner of wetlands. In some places, they also nest along streams with brushy or shrubby borders, a habitat more typically associated with the Louisiana Waterthrush. The forests that shelter their shaded habitats range from coniferous to mixed to deciduous, and in the taiga and boreal forests of Canada and Alaska, rivers bordered with willow and alder are typical habitats. In easternmost Canada, pairs occasionally nest well away from wetlands, so long as the forest is moist and has ground cover. Although they don’t nest in clearcut areas, Northern Waterthrushes sometimes forage inside them, if there are pools of water conducive to foraging. Migrants turn up in all manner of wetland habitats, even very small ones, and tend to remain near or within shrubs or ground cover. Migrants use mangrove swamps. In Mexico, they are most often found in lower, wetter areas of mangroves, rather than in the higher parts. Wintering birds also use this habitat, as well as wet forests at higher elevations.

Back to top

Food

Food Insects

Northern Waterthrushes eat mostly larval and adult insects, along with spiders, snails, clams, fish, and salamanders. Specific insect prey include stoneflies, mayflies, caddisflies, ants, and weevils. They forage mostly by walking into shallow water, where they pick prey from the water’s surface or below it, from mud, from wet leaves, or from vegetation, logs, or rocks. They sometimes catch flying insects on the wing or glean insects from low vegetation by leaping or hovering.

Back to top

Nesting

Nest Placement

Nest Ground

Females apparently select the nest site. The nest is made within root tangles of fallen trees, in clumps of vegetation near water, or inside niches in the banks of streams. In the far north, pairs build nests in marshy areas inside willow thickets.

Nest Description

The pair builds the nest together, but the female probably does more actual construction. The nest is a shallow cup often hidden by vegetation and usually covered above, with a side opening and sometimes with an entranceway of leaves. It is made of grass stems, twigs, pine needles, mosses, and rootlets, lined with animal hair and fine grasses. The exterior of the nest may include mosses and liverworts, sometimes leaves. Nests measure about 2 inches tall by 4.2 inches across, with the interior diameter averaging 2.4 inches and interior depth 1.3 inches.

Nesting Facts
Clutch Size:3-5 eggs
Number of Broods:1 brood
Egg Length:0.6-0.8 in (1.6-2.1 cm)
Egg Width:0.6-0.6 in (1.4-1.6 cm)
Egg Description:

White with dark spots and scrawls concentrated around large end.

Condition at Hatching:

Naked and helpless

Back to top

Behavior

Behavior Ground Forager

Northern Waterthrushes walk along the water’s edge or along rocks and logs, bobbing the rear of the body and skillfully hopping over impediments as they seek prey. Their flight is swift and agile, sometimes with a bounding (undulating) quality when crossing open water. Males maintain and defend a territory within a larger home range that is used daily for foraging. This range might be as small as 9 acres or as large as 100 acres. Courtship involves males circling or following the female and vibrating the wings, calling and singing, often with raised crown feathers. The female responds by calling quietly. To define their territory, males sing both a primary song and a flight song and chase out rival males by flying at them. Clashes with rivals also include a “crouch-walk” display that involves two males walking toward one another in horizontal posture with wings quivering and tail fanned. Most wintering and some migrating birds, especially males, are also territorial, but individuals in low-quality (drier) habitats sometimes do not defend territories.

Back to top

Conservation

Conservation Low Concern

Northern Waterthrushes are numerous, and their population has grown by an estimated 54% since 1970, according to Partners in Flight, which estimates the global breeding population at 17 million. The species rates an 8 out of 20 on the Continental Concern Score, indicating it is a species of low conservation concern. Despite their large populations, Northern Waterthrushes die in numbers each year from hunting by cats and from collisions with large buildings and communications towers. Pollution, pesticides, drainage of wetlands, and other modifications of habitat are additional threats to the species. Rising sea levels, a result of global climate change, will impact mangrove forests, their main wintering habitat.

Back to top

Credits

Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sauer, J. R., J. E. Hines, J. E. Fallon, K. L. Pardieck, Jr. Ziolkowski, D. J. and W. A. Link. The North American Breeding Bird Survey, results and analysis 1966-2013 (Version 1.30.15). USGS Patuxtent Wildlife Research Center (2014b). Available from http://www.mbr-pwrc.usgs.gov/bbs/.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, USA.

Stephenson, T. and S. Whittle (2013). The Warbler Guide. Princeton University Press, New Jersey, USA.

Whitaker, Darroch M. and Stephen W. Eaton. (2014). Northern Waterthrush (Parkesia noveboracensis), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Back to top

Looking for ID Help?

Get Instant ID help for 650+ North American birds.

Try Merlin Bird ID