| Re: Seasonal timing for spring avian surveys GRATIOT COUNTY |
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----Original Message----
From: McGinnis, Ryan Date: 3/16/2011 10:22:17 AM Subject: Seasonal timing for spring avian surveys
Hi
Monica, We
will be conducting spring 2011 migratory raptor and songbird studies at
a proposed wind energy facility in Gratiot County Michigan. This
will be the second year of data collected for this proposed project.
Currently we are in the process of developing our field schedule for the
2011 season, and are seeking your advice as to when the optimum time to
conduct these surveys would be. We will be conducting (4) 8-hr
raptor surveys from a fixed point, and 4 (4-hr) morning point count
surveys at a number of points throughout the proposed project boundary.
We’d like to conduct these surveys roughly a week or two apart to
cover the entire spring season. Last year I believe we began our surveys
the last week of March and finished the second week of May. In
your opinion, does this time-span sound accurate for catching migration
in central Any
guidance you could provide will be greatly appreciated, Thanks Ryan Reply to Ryan McGinnis 24 Mar 2011
Dear Ryan, Thank you for contacting me. First, please allow me to state that the time/duration of your planned raptor survey is inadequate. Hawk Migration Association of North America [HMANA] siting policy states that a minimum of 3 years of "full-time" [ March through May] coverage is necessary to begin to determine migratory patterns/numbers. Please refer to the HMANA web site for their complete statement: http://www.hmana.org/Hawkcount_Wind_Siting.
I myself have been doing the Port Crescent survey on a part-time [100 hours or so per season] for 10 years and still cannot make a definitive statement as to the scope of the migration in Huron County. Any data you are able to gather with your planned days/hours of observation will not yield a valid conclusion.
That stated, these are my recommendations for your survey. First, I suggest that setting specific 'dates' will not give you an accurate picture of migration [of any species]. Birds do not move in the rain; they do not move against strong winds, etc. Their numbers vary daily according to the weather. Thus I recommend that you establish a target 'window' and conduct your surveys when the weather is conducive to migration. [To simplify, south winds with a front approaching from the west or south] To do otherwise would be scientifically unsound. I should mention that I did forward your request to David Peters FWS as he will have more knowledge about avian migration in that area of the state.
As to peak raptor migration: at PCSP it occurs the last two weeks in April and the first week in May, all dependent on the weather. Peak passerine numbers start after that.
I do thank you for seeking input from me, Ryan, and hope you will take my information into most serious consideration.
Sincerely, Monica Essenmacher Head, Port Crescent Hawk Watch Huron County |