170 likes | 292 Vues
American Oystercatcher Breeding Distribution and Population Estimate in North Carolina. Susan Cameron and David Allen NC Wildlife Resources Commission. Introduction. 2004 represents the first year NC has conducted a coast-wide survey for breeding oystercatchers
E N D
American Oystercatcher Breeding Distribution and Population Estimate in North Carolina Susan Cameron and David Allen NC Wildlife Resources Commission
Introduction • 2004 represents the first year NC has conducted a coast-wide survey for breeding oystercatchers • In the past, breeding surveys have been focused at just a few sites • complete surveys along Cape Hatteras National Seashore beginning in 1999 • complete surveys along Cape Lookout National Seashore beginning in 1998
average # pairs year AMOY Breeding Population Trends at Cape Hatteras National Seashore Marcia Lyons, NPS
average # pairs year AMOY Breeding Population Trends at Cape Lookout National Seashore Jeff Cordes, NPS
Introduction • 2004 represents the first year NC has conducted a coast-wide survey for breeding oystercatchers • In the past, breeding surveys have been focused at just a few sites • complete surveys along Cape Hatteras National Seashore beginning in 1999 • complete surveys along Cape Lookout National Seashore beginning in 1998 • This presentation will focus on the 2004 surveys
General Description of Coast • NC’s coastline extends approximately 311 miles from VA to SC • NC has distinct northern and southern regions • North of Cape Lookout characterized by large back barrier sounds and long barrier islands with few inlets • South of Cape Lookout characterized by small back barrier sounds and short barrier islands with numerous inlets • Human disturbance and predation is a concern at most barrier island sites and some estuarine sites
Northern Coast • Currituck Sound – primarily fresh and has no inlets to the ocean and no dredge islands; beach front has very little overwash and heavy human disturbance • Pamlico Sound – large brackish sound with three inlets; dredge islands around inlets; east side has narrow barrier islands subject to overwash and the west is extensive brackish marshes • Because the tides are primarily wind driven in northern sounds, intertidal flats are not extensive except for areas adjacent to inlets
Southern Coast •Core Sound and smaller southern sounds – high saline estuaries with lunar driven tides • From Morehead City south is a chain of dredge islands created during the construction on the AIWW in the 1930s • Groups of dredge islands also clustered around inlets and in the Cape Fear River • Shell rakes present along estuaries south of Morehead City
NC Survey Areas Morehead City
Methods • Most surveys conducted in conjunction with this year’s colonial waterbird surveys and piping plover surveys (from early May – early July) • Surveyed additional areas along AIWW and Core Sound by boat and on foot • Covered portions of Pamlico/Albemarle Sounds by air with some ground truthing
Results • 337 pairs of oystercatchers counted • Majority found in southern half of NC • Many found on remaining undeveloped barrier islands (e.g. Masonboro, Core Banks, Hatteras)
2004 Population Estimate of Breeding American Oystercatchers in North Carolina
# pairs county 2004 Distribution American Oystercatchers by Nesting Habitat in NC Counties
2004 Distribution American Oystercatchers by Nesting Habitat in NC Counties
Future Work • Hope to repeat coast-wide surveys every few years so can begin assessing state-wide trends in abundance and distribution • Increase protection efforts at some sites (e.g. Masonboro Island)
Records of NC Breeders Banded on Wintering Grounds • Sunset Beach • 1 banded in SC in 2001 • Wrightsville Beach • 1 banded in SC in 2002 • North Topsail/New River Inlet • 2 banded in SC in 2004 • 1 banded in GA in 2003
Acknowledgments • We are extremely grateful to Walker Golder with NC chapter of National Audubon for all of his help with the surveys • Special thanks to Marcia Lyons of Cape Hatteras National Seashore, Jeff Cordes of Cape Lookout National Seashore and Shiloh Schulte of NC State University for providing their breeding data • Many thanks also to staff of various State Parks and to the many volunteers who contributed to survey efforts