Louisiana Waterthrush - Ecology

Ecology

The male Louisiana Waterthrush does not sing on its wintering grounds before it leaves. It sings immediately when it arrives on its breeding territory. Whether it begins singing during migration is not known. When establishing his territory, a male sings vigorously nearly all day. After he acquires a mate, singing decreases quickly and he concentrates his singing into the morning hours. The breeding habitat is wet woodlands near running water and does not occur outside such areas as a breeder. However, during winter, the Louisiana Waterthrush mainly forages along flooded roads or trails, and in parks, lawns and gardens, rarely entering true forest, even forested wetlands, in the subtropics. The Northern Waterthrush prefers stagnant, swampy waters and is generally a more terrestrial forager. Louisiana Waterthrushes prefer dense vegetation along the water's edge for nesting, since this provides the main protection of nest from predation. Louisiana Waterthrushes nest in a rock crevice, mud bank or amongst tree roots, laying 4–6 eggs in a cup nest from late May to mid-June. Both parents construct the nest, which is built from wet, muddy leaves, pine needles, grass, and small twigs. The female Louisiana Waterthrush incubates the eggs for 12 or 13 days. The fledging period lasts for 9 or 10 days, with both adults feeding the young for a further 4 weeks.

They are one of a few passerine species that does most of its foraging in actively running water, which only the dippers are known for at the family level. Mostly they depend on aquatic insects, molluscs, and crustaceans. Occasionally ground-based insects, such as beetles and ants are taken, as well as flying insects, such as flies, which may be hawked on the wing. Alternately, they forage amongst the leaf litter. In circumstances where the insect prey is low, Louisiana waterthrushes can target prey as large as salamanders and small fish.