College of William and Mary
Potential Impact of Common Reed Expansion on Threatened High-marsh Bird Communities on the Seaside Phase III - Red Knot Stopover Ecology on the Virginia Barrier Islands
Project Description as Proposed:
Winter bird surveys will be will be conducted within selected high marsh patches of the seaside portions of Northampton and Accomack counties. Marshes will be selected and classified based on size, vegetation cover, and degree of Phragmites invasion. Individual marsh patches will be surveyed three times from December to February to produce bird density and species richness indices and used to determine the effects of Phragmites invasion on the high marsh community.
In recent months a consortium of groups including Virginia Tech, The Nature Conservancy, the Virginia Department of Game & Inland Fisheries, and the Center for Conservation Biology has formed to begin to initiate a research program to answer several of the open questions regarding Red Knots on the seaside of Virginia. Initial objectives include 1) conducting further aerial surveys to monitor island use and determine distribution as was done in the mid-1990s, 2) re-sighting previously marked birds to estimate residency times and local movements, 3) making limited observations to collect preliminary data on diet and foraging rates, and 4) conducting some limited trapping to begin to evaluate body condition.
Winter Surveys Background - The structure and functioning of high marsh habitats are currently threatened from direct human influence, invasion of exotic plant species such as the common reed (Phragmites), and sea level rise. Virginia's Seaside coastal zone support significant winter populations of declining bird species that are dependent upon high marsh habitat. The Saltmarsh Sharp-tailed Sparrow and Nelson's Sharp-tailed Sparrow are examples of two such species that breed throughout the northeastern US but winter in the mid-Atlantic. Population and habitat goals to conserve these and other species on the breeding grounds can only be met if complementary wintering habitat in the mid-Atlantic is also maintained. There is very little information on regional population sizes, density, and habitat use of these species in winter. Because of this, it is unclear how much wintering habitat is needed to support breeding population goals and objectives. The specific objective of this study is to investigate the relative impact of Phragmites invasion on the habitat use and distribution of wintering bird species. These data will also be use to integrate regional conservation priorities throughout these species complete annual cycles.
Red Knot Background - Over the past 20 years, the highly migratory population of Red Knot within North America has declined by approximately 90%. Concern for this species led to an application to the U.S. Fish and Wildlife Service for fast track consideration for federal listing under the Endangered Species Act and a large-scale investigation of conflicts between migrants and the horseshoe crab industry. Most of the conservation efforts to date have focused on Delaware Bay. In the mid-1990s 3 years of aerial surveys showed that numbers of knots moving through the barrier islands of Virginia between mid-May and the second week of June reach 8,000-10,000. A single survey on 25 May, 2005 showed similar numbers. This compares to 13,000 birds using Delaware Bay this past season. These findings suggest that the Virginia Barrier Islands may have more significance to the species than previously believed. However, unlike the birds staging in Delaware Bay, birds using the barrier islands do not depend on horseshoe crabs. There are many questions yet to be addressed for birds staging in Virginia that may have broad implications for the future of this species.
Bryan E. Watts, 804.698-4323; email@example.com
10/1/2006 - 9/30/2007; Project Completed
Final Product Received:
"Potential Impact of Common Reed Expansion on Threatened High-marsh Bird Communities on the Seaside: Wintering Bird Surveys of Selected High-marsh Patches" (PDF)
"An Investigation of Stopover Ecology of the Red
Knot on the Virginia Barrier Islands" (PDF)
Project Summary Provided by Grantee:
Potential Impact of Common Reed Expansion on Threatened High-marsh Bird Communities on the Seaside Phase III (Surveys of Wintering Birds within Selected High-marsh Patches)
Ninety-nine 250-m transects were established within 55 marsh sites on the Delmarva Peninsula of Virginia. Eighty-three transects were established within 45 high-marsh sites and 16 transects were established within lower marsh sites dominated by Spartina alterniflora. All high-marsh study sites were established in marsh complexes with at least 5 hectares of high marsh habitat and were selected to include marsh patches along the gradient of P. australis invasion and latitudinal position on the peninsula.
A total of 66,000 m of transects were surveyed, resulting in 1,364 detections of 63 species. The most commonly detected species were Yellow-rumped Warblers, Sharp-tailed Sparrow, and American Robins. Four species of high conservation concern; Sharp-tailed Sparrow, Marsh Wrens, Sedge Wrens and Seaside Sparrows, were found in significant numbers within marsh study sites. Sharp-tailed Sparrows, Marsh Wrens, and Sedge Wrens were detected along the entire gradient of the large marsh patches in the northern portion of the Virginia Delmarva Peninsula to the smaller marsh patches in the southern portion of the Virginia Delmarva Peninsula, regardless of P. australis presence. However, while these species were detected within P. australis, they were most often detected within marsh grass habitats.
Detections of Seaside sparrow were restricted mainly to the marsh patches on Parramore Island, and were never detected within P. australis. Full details in the report: Paxton, B. J. 2007. Potential Impact of Common Reed Expansion on Threatened High-marsh Bird Communities on the Seaside: Wintering Bird Surveys of Selected High-marsh Patches. Center for Conservation Biology Technical Report Series, CCBTR-07-13. College of William and Mary, Williamsburg, VA. 21pp. Data of bird observations, survey transects and transect vegetation was supplied to the Virginia CZM Program in the following layers highmarshwinterbirdobs, highmarshwintertransects, highmarshwinterveg.
Red Knot Stopover Ecology on the Virginia Barrier Islands
A total of 6 barrier islands were intensively surveyed during the 2007 migration season. A total of 60 line transect surveys were conducted between 28 April 2007 and 18 June 2007 on the barrier islands. Transects were positioned to cover the barrier islands with the most Red Knot use. A total of 18,770 Red Knots were detected on surveys, with 12,580 of those knots scanned and resighted, of which 642 were banded. A total of 277 individually marked Red Knots were detected at least once during the spring 2007 migration season. Full details in the report: Smith, F.M., A. E. Duerr, B.J. Paxton and B.D. Watts. 2008. An Investigation of Stopover Ecology of the Red Knot on the Virginia Barrier Islands. Center for Conservation Biology Technical Report Series, CCBTR-07-14. College of William and Mary, Williamsburg, VA. 35pp.
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