American yellow warblers are small, bright yellow birds that breed in North America and winter in Central and South America. They are one of the most widely distributed wood-warblers in North America. Yellow warblers like wetlands and are often found in marshes, swamps, and wet thickets. They also live in orchards and along streams and rivers with brushy, shrubby vegetation. In this article, we’ll take a closer look at the range and habitats where American yellow warblers live throughout the year.
Breeding Range
American yellow warblers breed across most of North America from Alaska and northern Canada south throughout the United States and into northern Mexico. Here is a map showing their breeding range:
They can be found breeding in all the continental United States except for the very southeastern states. Their breeding range extends north up through Canada’s boreal forests to the limit of the trees. Along the Pacific coast, they breed from southeast Alaska south to northern Baja California in Mexico.
In their breeding range, yellow warblers occupy a variety of wooded wetland habitats including marshes, swamps, bogs, fens, riparian woodlands along streams, wet thickets, and shrubby areas. They are often associated with willows and alders and other brushy, early successional vegetation.
Wintering Range
During the fall migration from August to October, most American yellow warblers migrate south to their wintering grounds in the southern U.S., Mexico, Central America, and northern South America. Their winter range extends from northern South America south to Peru and central Brazil. Here is a map of their winter range:
On their wintering grounds, yellow warblers inhabit a variety of semi-open to open habitats including woodland edges, dense scrub, forest openings, gardens, and areas with scattered trees and shrubs. Mangroves are a particularly important habitat. They are mostly found in lowlands but can winter up to elevations of about 6,500 feet in the Andes Mountains.
Migration
Yellow warblers are long distance migrants, with most birds traveling between 6,000 to 8,000 miles between their breeding and wintering grounds every year. They migrate at night and can cover around 100-250 miles per night during peak migration.
During spring migration from March to May, yellow warblers fly across the Gulf of Mexico and migrate north along the Atlantic coast, Mississippi River valley, and Central Plains. Fall migration occurs across a broader front with more birds crossing over land through Mexico and Central America.
Yellow warblers sometimes get off course during migration and show up as rare vagrants in Europe and Asia. There have been sightings as far west as Ireland and the United Kingdom and as far east as Japan.
Habitats
Breeding Habitats
As discussed above, American yellow warblers breed in wet, shrubby habitats across most of North America. Here are some details on the key habitats used:
- Marshes – They inhabit marshes from the northern boreal bogs to prairie pothole marshes further south.
- Swamps – Particularly swamps dominated by willow, alder, and other shrubby growth.
- Wet thickets – Such as shrub swamps, beaver meadows, edges of bogs/fens.
- Riparian woodlands – Nesting habitat is often associated with streams, rivers, lakesides.
- Orchards – Including abandoned or disused orchards.
- Early successional vegetation – Open woodlands, clearcuts, forest edges.
Preferred nesting sites have dense shrub layer vegetation from 3 to 10 feet above ground and often near openings in the shrub canopy. Nests are well concealed in forks of shrubs, often willow or alder.
Wintering Habitats
On their tropical wintering grounds, yellow warblers occupy a mix of habitat types including:
- Mangroves
- Forest openings and edges
- Overgrown pastures
- Dense thickets and scrub
- Gardens and parks with trees and shrubs
- Riparian corridors
Mangroves are an especially important winter habitat, providing cover and food resources. Other habitats allow for foraging while also providing protective cover from predators.
Population and Conservation
According to the Cornell Lab of Ornithology, yellow warblers have an estimated global population of 82 million individuals. Population trends seem to be stable or slightly increasing in most regions, so yellow warblers have a conservation status of Least Concern.
They face threats on their tropical wintering grounds, where habitat loss is occurring due to development, agriculture, and logging. Pesticide use also impacts their food supply of insects. Yellow warblers are vulnerable to brown-headed cowbird nest parasitism in parts of their breeding range.
Despite threats, yellow warblers remain widespread and common over most of their broad range. Protecting key wetland and mangrove habitats and reducing pesticide impacts will be important conservation measures for this bright and cheery North American breeding bird.
Conclusion
In summary, the American yellow warbler has an extensive range across North America and from northern South America to central Brazil. They breed in wet, shrubby habitats like marshes, swamps, wet thickets and occupy a variety of semi-open habitats in their winter range. Yellow warblers undertake long distance migrations up to 8,000 miles between their breeding and wintering grounds. With stable populations, they remain one of the most common and widely distributed warblers in North America. Protecting wetland habitats across their range will help ensure yellow warblers continue brightening up backyards and wetlands with their splash of sunshine yellow.
