Louisiana Waterthrushes breed along clear, perennial streams in mature deciduous or mixed forest, usually in hilly environments. They also breed in cypress swamps and other bottomland forests but avoid clearcut areas and young forests. Wintering birds in the West Indies and in Central and South America also use fast-flowing streams in hilly areas, less often in the lowlands, and they are downright rare in the mangrove forests favored by Northern Waterthrushes, though both species may be found there during migration.Back to top
Louisiana Waterthrushes prey on a great variety of insects and small vertebrates, most found in or very close to freshwater streams. They take adults and larvae or nymphs of caddisflies, mayflies, midges, soldierflies, craneflies, lacewings, stoneflies, butterflies, moths, aphids, dragonflies, damselflies, beetles (of many types), along with millipedes, woodlice, cicadas, scorpions, spiders, crayfish, earthworms, minnows, frogs, and salamanders. Their larger size enables them to take larger prey than the Northern Waterthrush, a species that overlaps Louisiana Waterthrush in both breeding and wintering ranges. They take most of their prey using rapid jabs of the bill, and they also move leaves in the water and at water’s edge to uncover prey. Less often, they catch flying insects on the wings or by hover-gleaning them from overhanging vegetation.Back to top
Males and females appear to choose the nest site together. Nests are typically within recesses along a streambank, often beneath a log or within a root tangle on the southern side of the stream. Both sexes contribute to the building of the nest.
Both sexes build the cup nest. They make the foundation of the cup nest from plant stems, pine needles, wet leaves, and dry leaves; some pairs also build an entranceway of dead leaves to the nest. Mud, often collected from the stream bed, holds the outer portion of the nest together. They line the interior with fine plant stems, rootlets, hair, and mosses. Nests measure about 6 inches wide by 4 inches tall; the inside dimensions are about 3 inches wide by 2 inches deep. The size of each nest appears to depend upon the size of the recess in which it sits.
|Clutch Size:||2-6 eggs|
|Number of Broods:||1 brood|
|Egg Length:||0.8-0.9 in (1.9-2.2 cm)|
|Egg Width:||0.6-0.7 in (1.5-1.7 cm)|
|Incubation Period:||10-14 days|
|Egg Description:||Creamy white with reddish brown splotches, usually concentrated around larger end.|
|Condition at Hatching:||Helpless with tufts of dark gray down.|
Louisiana Waterthrushes hunt prey along the edges of streams, where these active birds walk briskly and agilely among sticks and stones in pursuit of aquatic insects and small vertebrates. They do not swim or immerse themselves completely, but they wade, sometimes deeply, into water to obtain food, with sharp stabs of the bill, at times recalling a small heron. Prey is usually dispatched with a few blows before being consumed. Males maintain and defend a territory along a length of stream, but they do not guard the surrounding woodland as Northern Waterthrushes do. Territories can include as little as 295 feet of stream or up to 4,800 feet of stream. Courtship involves the male and female making short, paired flights and standing and facing one another, giving a short zizz call note. One study using banded birds found that about one-third of Louisiana Waterthrushes returned to their nesting area to breed with the same mate in consecutive years. To define their territory, males sing both a primary song and an extended song that the male uses when chasing away rival males in flight. Clashes with rivals or neighbors also include a display in which the two males face each other, open their bills to display their bright pink mouth lining, rapidly raise the wings above the back, then stiffly lower them. They use the zizz call at this time as well. Wintering birds are highly territorial. Remarkably, where their ranges overlap, Northern and Louisiana Waterthrushes feed near each other without conflict.Back to top
Partners in Flight estimates Lousiana Waterthrush population has increased by 34% since 1970. The organization estimates the global breeding population of 450,000 and rates the species a 12 out of 20 on the Continental Concern Score, indicating it is a species of low conservation concern. As a bird of forested streams, Lousiana Waterthrushes are sensitive to water pollution, forest fragmentation, and losses of habitat from infestations by introduced pests such as balsam wooly adelgid. They are sensitive to poor water quality, such as streams acidified or otherwise polluted from human activities, because those streams lack sufficient insect prey.Back to top
Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.
Mattsson, Brady J., Terry L. Master, Robert S. Mulvihill and W. Douglas Robinson. (2009). Louisiana Waterthrush (Parkesia motacilla), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
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