The mourning warbler (Geothlypis philadelphia) is a small songbird of the New World warbler family. Mourning warblers are neotropical migrants native to eastern and central North America and wintering in Central and South America. They tend to be found in dense second growth forests. They are very similar to the MacGillivray's warbler in appearance, especially in females and immature birds, but their breeding range does not overlap into the west.
The "mourning" in this bird's name refers to the male's hood, thought to resemble a mourning veil.
Identification
Mourning warblers are small songbird with yellow underparts, olive-green upperparts, a thin pointed bill and pink legs. Adult males have a gray hood, black lores and a black patch on the throat and breast. In the fall, this pattern becomes less bright and harder to distinguish from similar species; however they never have a broken eye ring. Females and immatures are gray-brown on the head with an incomplete eye-ring. They have a yellow-gray throat with a brown or olive tint to their breast. Both sexes can range from 10 to 15 cm (3.9–5.9 in) in length and 11–13 g (0.4–0.5 oz) in weight. Their wingspan is 18 cm (7.1 in). Winter ranges vary between latin and southern American countries. They are common in Ecuador, Venezuela and Colombia, but have also been found in Nicaragua, Costa Rica, El Salvador, and the Dominican Republic. Nests are around 6.3 inches across and 3.4 inches tall. Mourning warblers have young with gray tufts on their head and red mouths. Adult females are also known consume their eggs after their young hatch. The number of days for young to fledge is 7–9.
Migration
Mourning warblers begin to migrate south for the winter from northern United States and Canada in late August but sometimes leave as late as November. They arrive in central America in September through October. They begin their migration back north in March, but sometimes in May. When returning north, mourning warblers generally follow the coast of central America. They follow the Mississippi River and Ohio River valleys before they disperse to the east and west. Mourning warblers that breed in the east follow the Appalachian Mountain ranges and east coast. They reach their breeding grounds by May and June, and repeat the process.
Vocalization
The song of this bird is a bright repetitive warble. The warble consists of rolling phrases that sound that typically lower in volume at the end and can sound like "chirry, chirry, chirry, chorry, chorry." The call is a sharp chip. There are usually two different pitched calls, with one higher than the harsh chip. Male mourning warblers use calls to establish their territory and scare away other males.
Mourning warblers' calls vary between regions, known as regiolects. Regiolects are defined as differences in syllables. There are several regiolects found across the mourning warbler's range: A Newfoundland regiolect, a Nova Scotia regiolect, and an eastern and western regiolect. The eastern regiolect is found in Quebec and eastern United States. The western regiolect is found in Minnesota, western Ontario and Alberta. Some possible explanations are the island effect, geographical separations such as large bodies of water, and human development. However, they are still categorized as a species of least concern with 14 million estimated as a global breeding population by Partners in Flight.