Between 24 May and 13 June, 2005, Bryan Watts, Bill Williams, Mike
Wilson, Bart Paxton and Fletcher Smith from the Center for Conservation
Biology conducted spot mapping activities to estimate the size of the
Coastal Plain Swamp Sparrow (Melospiza georgiana nigrescens) breeding
population in Mulberry Point Marsh on the Rappahannock River. This site
contains an extensive, privately owned, brackish marsh with numerous shrub
hummocks. The possibility of the site supporting a breeding population was
discovered in June of 2004 when Fred Atwood reported 14 birds and an
individual carrying food (Virginia Birds 2004). The survey efforts in 2005
have documented 41 singing males. Five nests were discovered on 24 May. No
further nest searching has been conducted.
The Coastal Plain Swamp Sparrow was first described from a specimen
taken along the Nanticoke River on the Eastern Shore of Maryland in 1947.
The center of abundance for the population has been southern New Jersey and
Delaware along Delaware Bay. Atlas work in Maryland in the 1980s indicated
a population on both the eastern and western shores of the upper Chesapeake
Bay. Recent surveys have shown dramatic declines, particularly in Coastal
Maryland. Other than a small number of observations in the Dyke Marsh area
on the Potomac River there are no modern breeding records for Virginia. Due
to small population size, declining trend, habitat specialization and
apparent vulnerability it has been recommended that the population be given
federal and state conservation status throughout its range.
The Mulberry Point population extends the known breeding range for this
form a considerable distance to the south and represents the largest
concentration of breeding currently known throughout the Chesapeake Bay. An
individual was detected in Otterburn Marsh further up the Rappahannock River
during this same time period and work by CCB to further refine the size and
extent of this population is ongoing.
The Coastal Plain Swamp Sparrow appears to occur in marshes within a
fairly narrow salinity band from oligohaline to tidal fresh. All of the
territories in Mulberry Point Marsh were positioned in portions of the marsh
that contained lush meadow vegetation including rushes, three-square,
saltmeadow hay, and scattered salt bush. These marsh types occur on the
Potomac River between Caledon and Washington D.C., on the Rappahannock River
between Tappahannock and Port Royal and at the point of transition between
tidal and nontidal portions of many Bay tributaries. The Center for
Conservation would be interested in any observations of this rare sparrow in
coastal Virginia during the months of June, July, and August.
Bryan D. Watts
Center for Conservation Biology
submitted for Bryan by
Mike Wilson
Center for Conservation Biology
College of William and Mary
PO Box 8795
Williamsburg, VA 23187-8795
phone: 757-221-1649
fax: 757-221-1650
www.ccb-wm.org
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