Rare Species Guide

  Synonyms

Seiurus motacilla

  Basis for Listing

The Louisiana Waterthrush (Parkesia motacilla) reaches the northwestern limits of its continental breeding range in Minnesota (NatureServe 2024). An uncommon and locally distributed breeding species, most Louisiana Waterthrushes nest in two regions in the state. In southeastern Minnesota (The Blufflands and Rochester Plateau subsections), Louisiana Waterthrushes are most frequently found along swiftly flowing streams in steep-sided forested valleys which is typical habitat for this species. In east-central Minnesota (St. Paul-Baldwin Plains and Moraines, Mille Lacs Uplands subsections), they are largely associated with forests and streams along the St. Croix River and its tributaries. Historically, Louisiana Waterthrushes occurred in the Twin Cities metropolitan area along tributaries of the Minnesota River, but they largely disappeared from this region in the 1950s (Janssen 2019). In recent years, they have been infrequently found along streams in the Minnesota River Valley; however, forest and water quality in this region appear to remain marginal for this species.

Invasive plant species, such as reed-canary grass (Phalaris arundinacea) and garlic mustard (Alliaria petiolata) have greatly increased along many streams where Louisiana Waterthrushes occur, but the impacts on the species’ populations are unknown. Because the Louisiana Waterthrush requires high-quality mature forest along rivers and streams, it is sensitive to disturbance of forest cover, streambeds and associated microhabitat features, as well as water quality. This habitat sensitivity, along with its relatively small population and limited distribution, has resulted in its listing as a special concern species in Minnesota.

  Description

There are two species of waterthrush, both of which nest in Minnesota. The Louisiana Waterthrush is best distinguished from the similar Northern Waterthrush (Parkesia noveboracensis) by its loud, distinctive song consisting of 2-3 clear, slurred whistle followed by a rapid jumble of notes. Physical differences between the two waterthrushes are subtle. Both have brown upperparts, whitish underparts with dark streaks, prominent white eyebrow stripes, and tail-wagging behavior.  In general, the Louisiana Waterthrush has a slightly longer bill, a wider whiter eye stripe that broadens behind the eye, brighter pink legs, and buffier flanks. In addition, the Louisiana Waterthrush has an unstreaked throat, as opposed to the streaked throat of the Northern Waterthrush. This latter feature is quite variable however, and some Northern Waterthrush have a largely unstreaked throat.

The preferred breeding habitat of the Northern Waterthrush differs from that of the Louisiana Waterthrush in that Northern Waterthrushes prefer slow-moving water or pools, usually with heavy shrub cover (often alder) and an overstory of trees such as ash or white cedar. The breeding ranges of the two waterthrushes are largely separate, only overlapping in east-central Minnesota. This area of overlap, however, is in the region where Louisiana Waterthrushes often nest along slower-moving streams in level terrain, such that habitat cues should be used with caution.

  Habitat

Typical Louisiana Waterthrush habitat consists of steep-sided, forested valleys with swiftly flowing streams that have rocky stream beds and riffles (Mattsson et al. 2020). In southeastern Minnesota, Louisiana Waterthrushes are most frequently found in this classic habitat, with key native plant communities being mesic hardwood forests.  Of particular importance is southern wet-mesic hardwood forest in narrow stream valley bottoms, with other mesic forest native plant communities on adjoining slopes. In slightly broader stream valleys, floodplain forest can be important on valley bottoms, though associated forested slopes are still present. Louisiana Waterthrushes are rarely found in the wide, broad floodplains along large rivers such as the Mississippi. Important microhabitat features for nest sites include small hollows or cavities within eroded stream banks, or exposed root masses immediately adjacent to streams. Other crucial stream habitat components include adequate foraging sites of exposed/emergent rocks at the waters’ edge or within a stream, submerged leaf litter, and areas of water less than 3-5 cm (1-2 in.) deep (Stucker 2000).

Louisiana Waterthrush habitat in the northern portion of their Minnesota breeding range differs somewhat from that in the southeast. Along the St. Croix River and its tributaries (particularly the Kettle River), steep-sided stream valleys are not as prevalent, though mesic hardwood forests are still important. In this region, floodplain forest and wet forest gain in importance for Louisiana Waterthrushes. While smaller flowing waterways remain a key habitat feature, these may consist of seepage areas at the bases of steep slopes (Eliason and Fall 1989), tributary streams flowing through the relatively level floodplain, or other small channels with slow-moving water.

Key habitat features common to both regions are mature, closed-canopy forest. Mesic hardwood, floodplain, and wet forests can provide suitable forest cover. Fire-dependent forests rarely provide suitable Louisiana Waterthrush habitat. Other characteristics of unsuitable habitat include dense herbaceous vegetation that is usually associated with a lack of a closed forest canopy, dense shrub cover, and/or streams without a shallow water-terrestrial interface (e.g., steep, eroded mud riverbanks or large rock rip rap).

  Biology / Life History

The Louisiana Waterthrush winters in Central America and the West Indies. In Minnesota, Louisiana Waterthrushes return to breeding areas in mid-April, and nesting activities are well underway by early May. This is one of the earliest nesting warblers in the state; consequently, it has probably been overlooked in many areas because singing activity has largely ceased by late May and June when most breeding bird surveys are conducted. In breeding areas, Louisiana Waterthrushes occupy well-defended breeding territories. Their linear territories follow a stream bed and can vary regionally from 400-900 m (1310-2950 ft.) in length (Mattsson et al. 2020). The Louisiana Waterthrush typically builds its nests in small hollows or cavities within the root mass of upturned trees along the bank or stream side or under fallen logs. The female lays an average of 5 eggs, which hatch after 13 days. The young fledge approximately 9 days after hatching. Major food items are aquatic invertebrates.

  Conservation / Management

Louisiana Waterthrushes require mature deciduous forest adjacent to streams. In southeastern Minnesota, most stream valleys have been disturbed by grazing, tree removal, and/or cultivation. Stream valleys with insufficient canopy cover (less than 80%-90%) and the resultant dense herbaceous layer dominated by graminoids or weedy forbs are unsuitable for this species. Management considerations for Louisiana Waterthrush habitat in southeastern Minnesota include maintaining mature stream-side forests, providing or maintaining nesting habitat in stream banks, and increasing riffle areas and shallow stream edges (Stucker 2000). Louisiana Waterthrushes also require relatively large tracts of forest. Although the minimum width of forest corridors necessary for waterthrushes is unknown, most suitable forested stream valleys in Minnesota were a minimum of 300 meters wide (often 2-3 times that distance). Other potential threats to Louisiana Waterthrushes include stream siltation and poor water quality because of various human land uses (Mattsson et al. 2020).  Although brood parasitism by Brown-headed Cowbirds (Molothrus ater) in southeastern Minnesota is low for the Louisiana Waterthrush (Stucker 2000), it remains a conservation concern. When habitat management for trout is proposed in occupied or high-quality Louisiana Waterthrush habitat, care should be taken to maintain microhabitat elements important to this rare species. Invasive plant species, particularly garlic mustard (Alliaria petiolate) and reed canary grass (Phalaris arundinacea) are becoming established in many streams in southeastern Minnesota. Dense infestations of either of these invasives could have serious, detrimental effects on waterthrush habitat.

  Conservation Efforts in Minnesota

Breeding bird surveys by the Minnesota Biological Survey (MBS) and research in southeastern Minnesota have greatly increased our knowledge of the distribution, habitat use, ecology, and management of Louisiana Waterthrushes in Minnesota. Stucker (2000) identified microhabitat features important to this species and investigated the effects of trout habitat improvement on waterthrushes in southeastern Minnesota. Because a vast majority of Louisiana Waterthrushes in southeastern Minnesota occur along designated trout streams, trout stream restoration can affect waterthrush populations. Habitat improvement strategies that reduce the shallow-water-terrestrial interface (e.g., small, exposed rocks within the streambed or woody debris such as logs or branches) could negatively impact waterthrushes. However, trout habitat improvement projects in poor waterthrush habitat can benefit waterthrush populations if they add key microhabitat features, stabilize eroded banks, and improve water quality. During the 2009-2013 Minnesota Breeding Bird Atlas, Louisiana Waterthrushes were found in 10 blocks in 9 counties (Pfannmuller et al. 2017). Bird surveys by MBS documented Louisiana Waterthrushes in the equivalent of 41 blocks in 12 counties. Continued surveys, including re-survey of historic waterthrush streams and surveys of new areas of potentially suitable habitat, leading to establishment of monitoring routes along key streams will allow a better understanding of the status and viability of Minnesota’s Louisiana Waterthrush population into the future.

  Authors/Revisions

Steven P. Stucker (MNDNR), 2025

(Note: all content ©MNDNR)

  References and Additional Information

Eliason, B. C., and B. A. Fall. 1989. Louisiana Waterthrushes in Washington County: results of the 1988 Minnesota County Biological Survey work. Loon 61:34-37.

Janssen, R. B. 1987. Birds in Minnesota. University of Minnesota Press, Minneapolis, Minnesota. 352 pp.

NatureServe. 2008. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.0. NatureServe, Arlington, Virginia. . Accessed 3 June 2008.

Robinson, W. D. 1995. Louisiana Waterthrush (Seiurus motacilla) . Number 151 in A. Poole and F. Gill, editors. The birds of North America. The Birds of North America, Inc., Philadelphia, Pennsylvania.

Stucker, J. H. 2000. Biodiversity of southeastern Minnesota forested streams: relationships between trout habitat improvement practices, riparian communities and Louisiana Waterthrushes. Thesis, University of Minnesota, Minneapolis, Minnesota.