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Accession Number 5005121

Title Effects of Disturbance and Predation on Nesting American Oystercatchers

Project Description Problem Statement: The American Oystercatcher (Haematopus palliatus) is one of four shorebird

species in highest need of conservation attention ("extremely high") according to Hunter (2001)

in The Southeastern Coastal Plains-Carribean Regional Shorebird Plan (SE Regional Shorebird

Plan) of the U.S. Shorebird Conservation Plan. George (2001) estimated extremely low American

Oystercatcher's nesting success in the egg stage (12-27%) and in success at fledging young

(0-6%) in recent studies along the Georgia coast. In North Carolina from 1997-1999, Davis et al.

(2001) found that only 13% of the nestshatched at least one egg (n = 245 nests). Prior to these

two studies, Nol (1989) also found low hatching success (13-14%) for American Oystercatchers in

Virginia. These apparent nesting and fledging successes will more than likely not sustain a stable

or increasing population. Hunter (2001) summarized that potential factors affecting oystercatchers

during the breeding season include vehicular use on beaches and public use of beaches in

general, especially where pets (i.e., dogs) are allowed to run freely. In Georgia, George (2001)

found that the most frequent direct causes of nest failure were predation and flooding from high

spring tides and storms. Failures of nests in North Carolina were also attributed to predation

(76%) and storm overwashes or severe weather (Davis et al. 2001). Both direct and indirect factors

likely result in poor reproductive success. Davis et al. (2001) also hypothesized that predators,

such as feral cats and racoons (Procyon lotor), which are more abundant in areas of human

activity may reduce survival of oystercatcher nests and hatchlings. Rappole (1981) suggested that

vehicular traffic from residents and all-night surveys for turtle nests may cause oystercatcher

nesting failures on Little Cumberland Island, Georgia. Recent studies in Georgia have not focused

on exact identification of causes of nest, egg, and hatchling losses; hence, studies are needed to

identify these causes specifically. Additional studies are needed to identify effects of disturbances

(e.g., dogs, people, or vehicles), survival through fledging, and causes of mortality for the

American Oystercatcher (Davis 2001, George 2001, Hunter 2001). Research objectives of the SE

Regional Shorebird Plan (Hunter 2001) that coincide with concerns of the Georgia Department of

Natural Resources and the investigators of this study are: 1) to determine depredation levels and

its sources for oystercatcher nests in the egg and hatchlings stages, 2) to determine disturbance

tolerance levels (primarily relative to activities of humans and their pets) and its effect on

oystercatcher nesting success, and 3) to assist by providing samples for a study of contaminants

in oystercatchers and their eggs. Quantifying the direct and indirect effects of human disturbance

(beach driving, pedestrian traffic, ATV traffic especially by technicians monitoring sea turtle nests,

and dogs) and the effects of predator abundance will be vital to future management of the

American Oystercatcher and its habitat within the southeastern region.Methods: We propose to

establish study sites on two barrier islands (e.g., Cumberland Island, Little St. Simons Island) that

provide nesting habitat for 12 or more oystercatcher pairs and that receive beach use from

recreational boaters and sea turtle technicians. Each island will also be divided into disturbed and

undisturbed areas. Oystercatcher nests will be located and monitored from March to July during

two nesting seasons. To assess depredation of nests, we will visit each nest every 2-3 days and

use tracks and other signs to identify predators if a nest fails because of predation. Video

monitors (with infrared for nighttime monitoring) will be used on randomly selected groups or single

nests in each area (disturbed and undisturbed) to monitor disturbances. Video techniques and

sampling will be identical to studies being conducted concur

Keywords american oystercatcher, beach, coastal islands, disturbance, georgia, nesting success, pets,

predation, shorebird, survival, telemetry,

Principal Joseph M Meyers, USGS Patuxent Wildlife Research Center: joe_meyers@usgs.gov; Sara H

Investigators Schweitzer, Warnell School of Forest Resources: schweitz@smokey.forestry.uga.edu;

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