The Cerulean Warbler is one of the most imperiled forest
songbirds of the eastern deciduous forest. It has declined
about 70% since 1966 when the Breeding Bird Survey
program began. Its declines are greatest in the center of its breeding range,
the Mississippi River Valley. The Pennsylvania story is a
bit more mixed. The Cerulean seems to have declined in
the western part of the state, especially the southwest, but
also has increased along some of our ridges, the Allegheny
Front, and in some eastern counties.
Oddly, the history of the Cerulean is one of expansion
into eastern Pennsylvania forests as well as losses
elsewhere.
The Cerulean is certainly a forest canopy songbird that
tends to be found in larger scale forests.
Pennsylvania is a really critical state for Cerulean Warbler
because of its commanding position in the Appalachian
Mountains and its many miles of riparian forest and
ridgetops.