Paul
Time to split the subspecies?
George

----- Original Message ----- 
From: "Paul O'Brien" <>
To: <>
Sent: Tuesday, January 23, 2007 4:10 PM
Subject: Re: [MDOSPREY] What happened to the Bewick's wren?


> Curiously, of the ten recognized subspecies of Bewick's Wren, only the
> nominate bewickii of the east has declined.   The other subspecies are 
> stable or
> increasing.   Could there be a genetic susceptibility factor?   Just 
> curious.
>
> Paul O'Brien
> Rockville, Mont. Co., MD
>
> In a message dated 1/23/07 3:55:13 PM,  writes:
>
>
>> 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>.
>>
>