Demise of the Eastern Bewick's Wren

Eastern Bewick's Wren
Cindy Chow
Bewick's Wren
The Bewick's Wren is a common and familiar bird of brushy habitats throughout much of the western United States.East of the Mississippi River, however, this species is very rare -- in fact few modern-day birders have ever seen one there. Historical records indicate that the Bewick's Wren was a fairly common inhabitant of eastern states as well, and in particular, a distinctive subspecies was resident in the Appalachian Mountains.Documenting the disappearance of a species is difficult because we often must rely on anecdotal accounts or personal memory. Now that the nearly 100 years of Christmas Bird Counts are accessible in a relational database, we have an unprecedented ability to investigate long-term changes in bird populations, such as the Bewick's Wren. In the accompanying graph, we can see that this wren was seen fairly regularly on eastern CBCs from at least 1949 through the mid-1970s, with 30 or more individuals
Trend Graph of Eastern Bewick's Wren from CBC data
Graph courtesy Cornell Lab of Ornithology
Trend Graph of Eastern Bewick's Wren from CBC data
found each year at roughly 20 different sites. Beginning in 1977, the eastern population began to crash, and it essentially has never recovered.Even in places like Nashville, Tennessee, where 5-to-10 Bewick's were found in early years, this number dropped during the same period, and none could be found there after 1984. Reasons for this precipitous decline are not well understood -- the species was well adapted to human-disturbed habitats and was even famous for nesting in old cars, junkyards, and out-buildings. Some authors believe that competition from the equally adaptive and more aggressive House Wren was a major factor. Having documented the Bewick's Wrens demise in the East, the challenge now will be for birders and ornithologists to locate remaining populations and devise a strategy for their long-term protection. Having documented the Bewick's Wren's demise in the East, it will be interesting to see if the decline will spread farther west and if there is anything we can or need to do to stop it.

Ken Rosenberg, Cornell Lab of Ornithology, 1999