Ruth Boettcher VA

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					 Breeding Distribution of American
Oystercatchers in Lower Chesapeake
 Bay and 2003 Breeding Population
        Estimate for Virginia

 Ruth Boettcher, Tom Bidrowski and Gary Costanzo
     Virginia Department of Game and Inland Fisheries
                            and
                  Bryan Watts, Ph.D.
             Center for Conservation Biology
               College of William and Mary
American Oystercatcher Breeding
Distribution in Lower Chesapeake
                Bay
Introduction
• In the past, oystercatcher survey efforts have
  largely focused on the barrier islands (annual
  waterbird surveys 1975 – 2003 by Williams et al.
  and plover/oystercatcher surveys 2000-2003).
• 2003 represents the first year Virginia has
  attempted to determine a statewide breeding
  population estimate for oystercatchers.
• This presentation reveals results from surveys
  conducted in the lower Chesapeake Bay.
Upper Bay                Eastern Shore
Islands

                               Chesapeake Bay,
                               VA Survey Areas
                       You are here

                           ATLANTIC OCEAN

       Western Shore
  GENERAL DESCRIPTION OF
LOWER CHESAPEAKE BAY SITES
•   Most of the Bay sites are vegetated islands with sandy
    shorelines and/or sand ridges where oystercatchers nest.
•   Many of the lower Bay sites are eroding fairly rapidly, which
    has resulted in a loss of suitable nesting habitat over the
    years.
•   Human disturbance is relatively minimal at most sites and
    limited to some recreational use, occasional use by
    watermen, and passing boat traffic. Grandview Beach, a
    recreational beach owned by the City of Hampton, receives
    the greatest amount of human disturbance of all.
•   Raccoons and other mammalian predators may occur on
    several of the sites, especially those in close proximity to the
    mainland.
•   Herring gulls and great black-backed gulls have established
    nesting colonies at many of the Bay sites. We are not sure
    what impact they are having on breeding oystercatchers.
     DATA COLLECTION METHODS FOR
      THE LOWER CHESAPEAKE BAY
1.   American oystercatcher breeding data were collected in an
     opportunistic fashion in conjunction with other surveys and
     monitoring efforts that spanned a three month period.
   –    Breeding black duck productivity surveys: Six out of 11
        Eastern Shore sites from April 2 – June 5.
   –    Piping plover and American oystercatcher survey: Grandview
        Beach (Western Shore) June 6.
   –    Colonial waterbird surveys: Throughout the remaining lower
        Bay sites from May 5 – July 2.
2.   Most site totals represent a count of pairs and single birds
     observed during a single visit. We used nest counts for those
     Eastern Shore sites that were monitored for black duck breeding
     activity from April through early June.
                    RESULTS - Eastern Shore
                Survey Period: April 2 – June 15, 2003
     SITE NAME            # OF PAIRS         SINGLE ADULTS            TOTAL BIRDS
 Scarborough Island             4**                    0                      8
 Finneys Island                 1**                    0                      2
 Cabin Island                   1**                    0                      2
 Parkers Island                 3**                    0                      6
 Pompco Creek Islet*             4                     0                      8
 Webb Is. Complex*               5                     1                     11
 Halfmoon Island*                4                     0                      8
 Channel Island                 1**                    0                      2
 Lower Bernard Island            2                     1                      5
 Upper Bernard Island           1**                    0                      2
 South Pt. Islet West            3                     0                      6
 TOTALS                         29                     2                     60
*Sites with evidence of breeding activity (chicks, cold or broken eggs, egg shell pieces).
**Actual nest counts.
       RESULTS - Upper Bay Islands
        Survey Period: May 12 – July 2, 2003
                    # OF        # OF       TOTAL
  SITE NAME        PAIRS   SINGLE ADULTS   BIRDS
Watts Island          4           1            9
Tangier Island       2           0             4
Shanks Island        3           0             6
Cheeseman Island     4           1             9
Great Fox Island     0           1             1
TOTALS              13           3             29
          RESULTS - Western Shore
       Survey Period: May 5 – June 10, 2003
                     # OF        # OF       TOTAL
  SITE NAME         PAIRS   SINGLE ADULTS   BIRDS
Grandview Bch.         6           0          12
Plum Tree Is. NRW     2           0           4
Goodwin Island        3           0           6
Guinea Marshes        5           0           10
Milford Haven         5           0           10
TOTALS               21           0           42
  RESULTS – All Lower Bay Areas
           Combined
                     # OF        # OF       TOTAL
  SITE NAME         PAIRS   SINGLE ADULTS   BIRDS
Eastern Shore         29           2         60
Upper Bay Islands    13           3          29
Western Shore        21           0          42
TOTALS               63           5         131
   2003 AMERICAN OYSTERCATCHER
 BREEDING POPULATION ESTIMATE FOR
              VIRGINIA
                                           # OF
                             # OF SINGLE ROOSTING TOTAL
      AREA                  PAIRS ADULTS  BIRDS*  BIRDS
Barrier Islands               302   52       0     656
Seaside Lagoon                224           20                84             552
Lower
Chesapeake Bay                63             5                0              131
TOTALS                       589            77               84            1,339
*Birds observed roosting in small flocks (5 – 17 birds) during surveys conducted prior
to the mid-June high tide flood event.
       ACKNOWLEDGEMENTS

• We are especially grateful to Ruth Beck, Mitchell Byrd,
  Sheila Faith, Heather Hollis, Catherine Markham, Bart
  Paxton, Mike Terry, Lou Verner, Marian Watts and Bill
  Williams for providing assistance with the
  oystercatcher/plover survey and Chesapeake Bay
  colonial waterbird surveys.
• Special thanks to Alex Wilke and Barry Truitt for
  providing their barrier island and seaside lagoon
  breeding data.
• Many, many thanks to Bart Paxton and Alex Wilke for
  making the breeding distribution maps.
reeding distribution maps.

				
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posted:7/27/2012
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