Virginia Museum of Natural History
Avian Habitat Restoration on the Virginia Barrier Islands: Test of a Non-Lethal Approach to Predation Management
Project Description as Proposed:
Removal of raccoons and red foxes is now employed as a tool for avian habitat restoration on the Virginia barrier islands by the US Department of Agriculture. The proposed task will assess the results of this predation management and test the use of an estrogen-induced food aversion to reduce raccoon predation on bird eggs. VMNH is running a field trial with free-ranging raccoons (through FY 2005 Task 9.06), to test the feasibility, practicality and potential expense of implementing such management. Depending on the outcome of these trials, VMNH will implement either a revised experimental field trial or a full-scale management application of this technology on perhaps 1-3 barrier islands during summer 2007. A second task will produce a GIS data base that will summarize the predation management effort and effects and help to identify high-priority locations for testing the aversive conditioning approach in 2007.
The Co-Principal Investigator, Ray Dueser, holds a 2 year permit from the Virginia Department of Game and Inland Fisheries for scientific collections. This permit authorizes the holder to collect and treat raccoons with oral estrogen in field trials in Northampton and Accomack Counties, the two counties within which the seaside barrier islands lie. His current permit expires December 31, 2006. Dr. Dueser will request a renewal in January of 2007. Approval is anticipated due to the fact that DGIF is one of the SHP partners and is supportive of this work.
There have been very promising results that came from the pilot field trial in summer 2005: With the deployment of estrogen-treated eggs in three artificial colonies on Skidmore Island, VMNH observed a decline in nest depredation from 68% on Day 1 to 31% on Day 2 to 18% on Day 3 to 5% on Days 5-11. Given the exceptionally high raccoon density on Skidmore (1.4 raccoons per hectare) and the difficulty of delivering an effective dose of aversive agent to 20+ raccoons at the same time, this result was very encouraging. The full-scale field trial being conducted in the summer 2006 has been designed to circumvent the logistic challenges encountered in 2005, and to provide a powerful test of the efficacy of oral estrogen as an aversive-conditioning agent.
Nancy D. Moncrief, (276) 666-8614; firstname.lastname@example.org
1/1/2007 - 12/31/2007; Project Completed
Final Product Received:
Project Summary Provided by Grantee:
Virginia Museum of Natural History personnel and colleagues from Utah State University and the University of Virginia have completed two tasks related to avian habitat restoration on the Virginia barrier islands.
The first task involved collecting outstanding records of mammal trapping (e.g., data forms, correspondence, and fieldnotes) from collaborators at USFWS, TNC, and VDGIF, and then producing a landscape-level GIS database and maps of predator capture locations on Assawoman, Metompkin, Cedar, Wreck, Ship Shoal, Myrtle, Smith, Skidmore and Fisherman islands for the period 2003 - 2007. These data, as well as information from track surveys, were used to address four questions: 1) How many raccoons and red foxes were removed each spring from each of nine target islands? 2) How many predators were thought to persist after the completion of trapping each spring? 3) How many predators were removed in the subsequent spring removal period? 4) Where has removal trapping been effective in reducing predator incidence?
The second task involved development of a set of education materials designed to aid managers in identifying areas on islands where a conditioned food aversion (CFA) strategy might reasonably be employed and assist managers in the effective implementation of such a strategy. These materials included (1) written instructions for preparation and deployment of eggs treated with an aversive agent, (2) written guidelines for site selection and site set-up for optimal application of a CFA treatment, (3) written instructions for camera operation and artificial colony maintenance, and (4) videos illustrating the actual techniques and methods involved in applying such a treatment.
Disclaimer: This project summary provides the federal dollars initially awarded to the grantee. Due to underexpenditure or reprogramming of grant funds, this figure may change. For more information on the allocation of coastal grant funds, please contact Laura McKay, Virginia Coastal Program Manager, at 804.698.4323 or email: Laura.McKay@deq.virginia.gov
A more detailed Scope of Work for this project is available. Please direct your request for a copy to Virginia.Witmer@deq.virginia.gov