Fall 2004 Avian Migration Surveys at the Proposed Deerfield Wind/Searsburg Expansion Project in Searsburg and Readsboro, Vermont


Title: Fall 2004 Avian Migration Surveys at the Proposed Deerfield Wind/Searsburg Expansion Project in Searsburg and Readsboro, Vermont
Publication Date:
April 01, 2005
Pages: 52

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Roy, R.; Pelletier, S. (2005). Fall 2004 Avian Migration Surveys at the Proposed Deerfield Wind/Searsburg Expansion Project in Searsburg and Readsboro, Vermont. Report by Stantec Consulting. pp 52.

Deerfield Wind, LLC has proposed to develop the Deerfield Wind/Searsburg Expansion Project, a wind power facility located on Federal land in the Towns of Searsburg and Readsboro, Vermont, (Figure 1) now known as the Deerfield Wind Project. The project would be constructed on approximately 80 acres of land in the Manchester District of the Green Mountain National Forest, adjacent to Green Mountain Power Corporation's (GMP) existing Searsburg Wind Facility, constructed in the mid 1990's. The expansion project will occur in two areas. The Eastern Expansion Area is located east of State Route 8, immediately south of the existing 11-turbine, 6 megawatt (MW) facility, and the Western Expansion Area is located on the west side of Route 8. The proposed expansion project consists of adding 20 to 30 wind turbines, capable of producing approximately 30 to 40 MW (megawatts). A unique feature of this proposal is that it will rely, in part, on the existing Searsburg facilities and infrastructure, including the substation and access road.


Field investigations for daytime and nocturnally-migrating birds were conducted by Woodlot Alternatives, Inc. (Woodlot) during the fall of 2004. The overall goals of the investigations were to:


  • investigate the magnitude and flight patterns of diurnally-migrating raptors (hawks, falcons, harriers, and eagles) across the project area and the surrounding vicinity ; and
  • document the passage of nocturnal avian migration in the vicinity of the Deerfield Wind Project area, including the number of migrants, their flight direction, and their flight altitude.


The Deerfield Wind Project is unique in that it is expanding upon the existing Searsburg Wind Facility, operated by GMP. Previous investigations for that project included daytime and nighttime studies of bird migration. This included hawk migration surveys in 1993 and 1994 (Martin 1993, 1994), breeding bird surveys (Capen and Coker 1994), nocturnal migration surveys (Kerlinger 1995, 1997), and an assessment of impacts to these resources (Kerlinger 1998). The fall 2004 migration surveys add to that knowledge base through a replication of some of that previous work and an expanded survey scope through the use of new methods.


The field surveys included day-time raptor migration surveys and a radar study of avian nocturnal migration activity. Surveys were conducted between September 16 and October 29, 2004. A total of 20 days of raptor surveys and 30 nights of radar surveys were targeted for this work.


Raptor surveys were conducted for 10 days. The survey sites and methods largely mimic those from previous raptor surveys conducted for the existing facility. One of the survey sites was the same as that used in those previous studies. The other site was in the same general area as the previous work (along the same ridgeline) area but took advantage of views provided by the existing facility that were not available during that previous work.


Radar surveys were conducted at three locations during the study, though only two of those three sites were surveyed during any given night within the study period. One survey site was in the Western Expansion Area and was surveyed during each night while survey effort was split between the other two sites, which included the existing facility (near the Eastern Expansion Area) and a low elevation site located just west of the Western Expansion Area.

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