Cerulean Warbler

Dendroica cerulea

  By Kimberly Vest

The Cerulean Warbler used to be one of the most plentiful breeding songbirds in the Eastern United States.  Because of the loss of mature deciduous forests to development and other practices, they are now listed as Threatened in some states and work is underway to have them protected under the Federal Endangered Species Act.  They are also under protection from hunting and harassment under the Migratory Bird Treaty Act of 1916.  Scientists are trying to find ways to restore the Cerulean Warbler’s habitat to keep them from becoming extinct.  One way that scientists are actively trying to keep this species from extinction is through the Cerulean Warbler Atlas Project (CEWAP).  This project was designed to help save these birds by finding out where they live and breed and what can be done to protect them from becoming extinct and to help decide if they should go under the Endangered Species Act.

 The Cerulean Warbler is in the Kingdom Animalia, the Phylum Chordata, Subphylum Vertebrata, Class Aves, Order Passeriformes, Family Parulidae, Genus Dendroica and Species (or scientific name) Dendroica cerulea meaning “true blue.”  Some other names include the Blue Warbler and/or Azure Warbler.

 Cerulean Warblers favor mature deciduous forests in rich swamps and bottomlands.  Their nests and eggs can be found at the tops of these soaring trees out on the far ends of the limbs. 

 Their diet consists mostly of insects.  The Dendroica cerulea works its way from the inside of the branch (closest to the trunk) outward and gleans insects from the leaves. 

 When in search for this tiny bird, which is only about 4-5inches long, you will find the adult male to be blue on its upperparts and bright white on its underparts with a dark breast band and dark back and side streaking.  The females have more of a greenish or bluish mantle and crown along with a pale supercilium (the region above the eyes) and a pale yellow breast and throat.  Both sexes are short-tailed and have two wide white wing bars.

 The song of this Warbler is much like that of the Parula Warbler except with the Parula Warbler the bzzz comes first and in the Cerulean it comes last.  The song can be heard as short, rapid, accelerating buzzy notes ending in a high, prolonged buzz.  It sounds something like this:  wee wee wee wee bzzz.

 The Dendroica cerulea has a wide breeding area that ranges along the East Coast of the United States, to Northeastern U.S. and Canada, through Central U.S. to Southeastern U.S.  Some of these states and provinces include: North Carolina, Virginia, West Virginia, Connecticut, Massachusetts, Rhode Island, Vermont, New York, Ontario and Quebec (Canada), Ohio, Michigan, Wisconsin, Minnesota, North Dakota, Nebraska, Kansas, Oklahoma, Texas, Louisiana, Mississippi, and Alabama. 

 In the winter, Dendroica cerulea can be found in Northern South America from Columbia and Venezuela to Southern Peru and Northern Bolivia.  Its migration route is mainly along the Mississippi River, across the Gulf of Mexico, through Central America.

With the recent four-year study of the Cerulean Warbler by the Cerulean Warbler Atlas Project and the Virginia Breeding Bird Atlas Project, there have also been sightings of these birds in Virginia.  They can be found in the Western and Northern mountains of VA, the Shenandoah Valley, along the Blue Ridge Parkway in Bedford County, and in Wildwood Park of Radford, Va.

 These birds have a positive economic importance for humans because they help with insect control.  They are of great interest to scientists as a marker of the overall ecosystem health in the North and South American forests.  People interested in seeing these birds, provide tourist dollars to the communities that the Cerulean Warbler can be seen in.  The work being done to protect the species’ habitat will also have enduring economic benefits.

Written spring 2004, as a service learning project for Dr. Gary Coté's Biology 102 class at Radford University.  Copyright Pathways for Radford.