Cerulean WarblerZhee Zhee ZiZiZiZi zzzzeeet. Its scarcity is part nature and part a product of developments taking place in the Appalachians over the preceding century, making it one of the species of highest concern in the region.
Range and Habitat
A Neotropical migratory songbird, the Cerulean Warbler breeds in the deciduous forests of the eastern and central U.S. The core of their breeding range occurs in the Appalachians from North Georgia and Alabama to New York, with the most concentrated populations in West Virginia, eastern Ohio, and the Cumberland Mountains of Eastern Tennessee. As winter approaches, they begin their southward journey across the Gulf of Mexico to stop in Belize, Panama, and the northern mountains of Columbia before wintering along the slopes of the Andes from Columbia to Peru and in northern Bolivia.
In the Appalachian portion of their breeding range, Cerulean Warblers seek out mature forests that contain tall deciduous trees with open canopies and gaps that allow sunlight to reach the forest floor, promoting the growth of saplings, shrubs, and other vegetation in the forest understory.
Decline and Status
Most present-day Appalachian forests developed in the wake of extensive land clearing that took place in the late 19th and early 20th centuries. Though they exist in large tracts, forests today are very different from those that existed prior to the 19th century. Present-day forests are very uniform with densely packed trees and closed canopies that lack the variety of overstory and understory habitat structure required by many songbirds. Coupled with the loss of tree species such as the American Chestnut, disrupted or absent natural disturbances like forest fires, and increased development across the landscape, mature forest health has been impacted dramatically, reducing the quality of these habitats for a variety of birds and wildlife. Within the Cerulean Warbler breeding range, over 50 percent of the historical forests have been cleared and replaced with farms, cities, and suburbs, according to the U.S. Fish and Wildlife Service (USFWS). The habitat that remains experiences pressures from energy development, especially surface mining for coal and natural gas extraction.
These changes led to the population falling sharply during the latter part of the 20th century. Breeding Bird Survey data indicates that Cerulean Warbler abundance fell at a rate of 3 percent per year since 1966. The small population size and threats to habitats throughout its range – from the conversion of native tropical forests to farms on its wintering grounds to the clearing of coastal woodlots used during migration for development - led to the petitioning of this species as threatened under the USFWS Endangered Species Act. Current Cerulean population estimates range from 400,000 to 560,000.
Since many forests that remain in the Appalachians do not have suitable habitat for Cerulean Warblers, the AMJV is working with partners to improve forest health and restore and expand the types of habitats preferred by this priority species. We are doing so through forest management techniques based on sound science.
AMJV partners completed a project in 2010 that allowed the scientific and management communities to learn how different timber management practices could be used to enhance Cerulean Warbler habitat. By studying the response of Cerulean Warblers and other forest birds to various timber harvesting treatments, AMJV and its partners are providing land managers and biologists with recommendations for enhancing habitat for ceruleans as well as a diverse bird community. As a result of this work, AMJV partners recently released new Cerulean Warbler Management Guidelines for Enhancing Breeding Habitat in Appalachian Hardwood Forests.