From what I understand, Bewick's Wren is essentially gone everywhere east of the Mississippi River. It is one of the most dramatic range losses of our lifetime, yet no one ever really had a handle on what was happening or what could be done about it. Speculation has focused on competition with House Wren and changing forests. According to Birds of North America (BNA), Bewick's Wren prefers open brushy woodlands. Our woodlands tend to be more closed-canopy than they used to be, and to have less underbrush (because of deer overbrowse). House Wrens seem to like the forests and edges that we have now. The BNA account suggests an initial colonization of the East by Bewick's Wren in the late 1800s right after a major deforestation, then a replacement of Bewick's Wren by House Wren from 1920 to 1980. House Wrens peck holes in the eggs of species that nest nearby, plus they prefer a more mature forest than does Bewick's Wren.

Retreat of Bewick's Wren may be similar to the retreat of Golden-winged Warbler, which has retreated behind an expansion of Blue-winged Warblers.

There has been no cold weather worth mentioning since the late 1970s in the United States east of the Mississippi and most songbirds that winter in the Eastern USA that are sensitive to cold weather have been expanding their ranges, not contracting (including Carolina Wren).

Bewick's Wrens have stable populations out west, according to the Breeding Bird Survey, so the species as a whole is doing fine, although the chances that it will ever re-colonize the East seem very low (although they did colonize the East from the West in the second half of the 1800s). The Ozark Mountains of Missouri seem to be the eastern-most stronghold for the species now.

Greg Butcher
Director of Bird Conservation
National Audubon Society
1150 Connecticut Avenue NW, Suite 600
Washington DC 20036
Tel.: 202-861-2242, ext. 3034
Fax: 202-861-4290


Protecting our Great Natural Heritage through the Important Bird Areas program,<http://www.audubon.org/bird/iba>, 
and the WatchList, <http://www.audubon.org/bird/watchlist>.