Louisiana Waterthrush

(Parkesia motacilla)

Status: Threatened (SARA 2007, ESA 2018)

Table of Contents:

Species Identification
Diet
Habitat and Range
Biology and Behaviour
Similar Species
Threats/Reasons for Being Endangered
Conservation and Recovery Strategies
How You Can Help

Species Identification:

The Louisiana Waterthrush is a large wood warbler that resembles a small thrush. Adults have brown backs and white stomachs streaked with light brown. They can be distinguished by a bright white stripe above their eye, and their bill is longer and thicker than most warblers. The Louisiana Waterthrush walks with a distinctive tail bob, and they are often found by forested streams. Their call is a series of whistles and chirps that are generally heard most often at dusk.

Diet:

The Louisiana Waterthrush’s diet is unusual for songbirds. They will walk along streams or ponds to feed on aquatic macroinvertebrates, or mature insects, and they will occasionally eat mollusks, amphibians, or small fish. The major groups of macroinvertebrate upon which this species relies (caddisflies, mayflies, and stoneflies), are sensitive to changes in water quality. They use rapid strikes from their bill to capture their prey, and will flip over leaves in the water to uncover any hidden prey.

Map taken from Wildlife Species Canada: https://wildlife-species.canada.ca/species-risk-registry/virtual_sara/files/cosewic/sr_Louisiana%20Waterthrush_2015_e.pdf

Habitat and Range:

Southern Ontario and Quebec are at the northern extent of the Louisiana Waterthrush’s breeding range. 99% of their population breeds in the eastern United States, extending west to Minnesota and south to Texas and Florida. Within Ontario, most populations are found in the Norfolk and Niagara Escarpment regions, with smaller scattered populations south of the Canadian shield. The breeding population in Canada ranges from 100-200 pairs, which is less than 1% of the total population.

Their wintering habitat usually consists of tall hills of tropical forest cover in Central America. Sightings of the Louisiana Waterthrush in The Land Between have been reported just west of Gravenhurst and Orillia, and north of Kingston.

The Louisiana Waterthrush breeds along forest ravines, which are streams that are located in mature deciduous or mixed forests, and generally avoid new forests or clearcuts. They prefer fast and clear running water in order to catch their prey. They prefer to nest among the roots of fallen trees, on stream banks, or in and under fallen rotting logs.

Biology and Behaviour:

The male Louisiana Waterthrush arrives at Ontario breeding sites in April or May and will fiercely defend his territory, which is generally along the stream. The male sings throughout the breeding season, and once paired they will both work together to make a cup-shaped nest made out of twigs, mud, and leaves. Nests are built on a rotting stump or log, or within the roots of an upturned tree. This is usually in a shaded area just a few meters from running water, and nearby shrubs are important to hide fledglings. 4-6 eggs are incubated for about two weeks, and are fed by both parents for another 10 days or so. Adults may be preyed on by raptors, and young are vulnerable to snakes, jays, and small mammals.

Similar Species:

The Louisiana Waterthrush looks quite similar to the more common Northern Waterthrush, which has thinner eyebrow lines that are more yellow “cream” coloured than the Louisiana's white lines. The Northern Waterthrush also has more distinct brown blotches under its tail. These species ranges do overlap, but they generally coexist with each other peacefully.

Threats/ Reasons for being at Risk:

1. Changes in water quantity: Throughout southern Ontario groundwater may be irrigated for agriculture, or used for municipal or industrial water supplies, which causes fluctuations in the surrounding watershed. Intensive land use like agriculture or urban activity can change the turbidity and acidity of streams, resulting in fewer available macroinvertebrates. Increased pollution such as road salt, pesticides, and nutrients are common in Ontario and will remain in the environment for long periods of time.

2. Tree loss due to logging and invasive forest pests: These lead to a loss of forest canopy, which is the Louisiana Waterthrush’s preferred nesting habitat. The Hemlock Woolly Adelgid (Adelges tsugae) is an invasive insect that is killing hemlock trees. It is a bigger problem in the Appalachian Mountains, and could become a threat to Canadian populations. Forest fragmentation increases the risk of predators and nest parasitism, and logging is reducing the number of mature forests and changing forest compositions.

3. Climate change and severe weather: Severe weather events and sudden cold snaps impact insect availability and breeding season. Droughts, flooding, and other severe weather events are likely to become more common. Since the Louisiana Waterthrush prefers fast and clear water, droughts and flooding are a huge issue for foraging since they change water flow and clarity.

4. Mortalities during migration: Like many migrating birds, the Louisiana Waterthrush is exposed to severe weather events while traveling, road mortalities, and mortalities while in urban areas if they collide with windows.

Conservation and recovery strategies:

The Federal Government recommends that groups work together to steward potential nesting sites on private property, and to collaborate with First Nations. They have also provided management recommendations for public lands including: wide riparian buffers (>100m) along at least 75% of stream lengths, and restrictions on recreational vehicle use within parks and protected lands.

How can you help?

It is very important to protect what little habitat remains in Ontario for this bird. Private landowners can play a big role by stewarding their land and protecting streams and forest habitats on their property.
During breeding season, avoid using ATV trails that cross through streams that could host the Louisiana Waterthrush or other forest birds.
Support sustainable forestry practices. It is important to leave the biggest trees, maintain wide riparian zones, and leave dead wood on the ground.

Additional Resources:

Cornell Lab of Ornithology page
Nature Canada profile
The Louisiana Waterthrush eBird profile has many pictures and sound clips

Sources:

Bezener, A. 2000.

COSEWIC. 2015. COSEWIC assessment and status report on the Louisiana Waterthrush Parkesia motacilla in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xi + 58 pp. (http://www.registrelep-sararegistry.gc.ca/default_e.cfm).

Environment Canada. 2012. Management Plan for the Louisiana Waterthrush (Seiurus motacilla) in Canada. Species at Risk Act Management Plan Series. Environment Canada, Ottawa. iii + 18 pp.