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 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 ) 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. Introduction

Chesapeake Bay, VA Survey Areas ATLANTIC OCEAN CHESAPEAKE BAY Upper Bay Islands EASTERN SHORE OF VA Western Shore Eastern Shore MARYLAND You are here

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 PAIRSSINGLE ADULTSTOTAL BIRDS Scarborough Island4**0 8 Finneys Island1**0 2 Cabin Island1**0 2 Parkers Island3**0 6 Pompco Creek Islet*40 8 Webb Is. Complex*51 11 Halfmoon Island*40 8 Channel Island1**0 2 Lower Bernard Island21 5 Upper Bernard Island1**0 2 South Pt. Islet West30 6 TOTALS29260 *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 SITE NAME # OF PAIRS # OF SINGLE ADULTS TOTAL BIRDS Watts Island 419 Tangier Island 204 Shanks Island 306 Cheeseman Island 419 Great Fox Island 011 TOTALS133 29

RESULTS - Western Shore Survey Period: May 5 – June 10, 2003 SITE NAME # OF PAIRS # OF SINGLE ADULTS TOTAL BIRDS Grandview Bch Plum Tree Is. NRW 204 Goodwin Island 306 Guinea Marshes 5010 Milford Haven 5010 TOTALS210 42

RESULTS – All Lower Bay Areas Combined SITE NAME # OF PAIRS # OF SINGLE ADULTS TOTAL BIRDS Eastern Shore Upper Bay Islands Western Shore TOTALS

2003 AMERICAN OYSTERCATCHER BREEDING POPULATION ESTIMATE FOR VIRGINIA AREA # OF PAIRS SINGLE ADULTS # OF ROOSTING BIRDS* TOTAL BIRDS Barrier Islands Seaside Lagoon Lower Chesapeake Bay TOTALS ,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.