Seiurus noveboracensisnorthern waterthrush

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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.

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.

  • 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.

  • Average mass
    18.7 g
    0.66 oz
    AnAge
  • Average basal metabolic rate
    0.28391 W
    AnAge

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.

  • Average eggs per season
    4
    AnAge

Lifespan/Longevity

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.

Communication and Perception

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: Positive

Feed on insects that are regarded as pests to humans.

Economic Importance for Humans: Negative

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Conservation 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

Contributors

Marie S. Harris (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

visual

uses sight to communicate

References

Eaton, Stephen, W.. The Birds of North America, No. 182, 1995.