The “Shoenfeld Estimator”: Where It Came From and How It Grew

By Frank Young

Back when the first wind farm was proposed for West Virginia ridges (year 2000), I was WVHC president. After about a year of recognizing myself as wind committee Chair, I decided that someone other than the President should Chair that committee.  Peter Shoenfeld let me know that he would Chair a WVHC wind committee if that would suit me.   After a few days of deliberation, I made that appointment.

My only strict admonition to Peter was to “keep it honest” (the debate about utility scale wind power in West Virginia) and without broadcasting dubious wind facility related ”studies” in the name of WV Highlands Conservancy simply for their value as sensational hype.  I was pleased that, although WVHC struggled mightily over wind energy issues for several years, Peter tried as best one could to keep the committee’s work honest.

By the time the bat and avian mortality studies at the then new Backbone Mountain wind farm were being conducted in 2003, I was on a “technical review committee” (TRC) that helped to oversee those studies.  Dr. Paul Kerlinger, an ornithologist, was contracted to design and oversee those mortality studies at Backbone Mountain. When the first round of study results were available to the committee, those results showed more projected numbers of bird mortality than actual dead bird counted. This came about as a result of several factors including searcher inefficiencies in discovering dead birds, numbers of dead birds removed by scavengers before searches were done, carcass decomposition, etc.

The mathematical formula Dr. Kerlinger had devised to project how many “unknown” birds died but were not found was beyond my mathematical comprehension. So I shared the TAC’s preliminary findings with our very own “in house” mathematician, Dr. Peter Shoenfeld.  Peter immediately took issue with Dr. Kerlinger’s formula for projecting numbers of dead birds that were not found via searches around wind turbine towers.  I did not understand much of anything about Peter’s expressed concerns with Kerlinger’s formula.  But I had a hunch that Peter knew what he was talking about.  So I contacted Dr. Kerlinger and told him of the concern Peter had expressed about Kerlinger’s formula.  I pretty much assumed that Kerlinger would dismiss Peter’s concerns as busybody intrusion into his work by some self-anointed “expert”.  But on the contrary, however, and after I told him that Peter did mathematical projections for the military and military contractors, Kerlinger said that he could use guidance from a professional mathematician in calculating numbers of unfound but nonetheless dead birds.  Kerlinger did not say so, but I felt that Kerlinger had some doubt about the reliability of his own estimator formula.

So in the second year (2004) of bat and bird mortality studies at Backbone Mountain, Peter was WVHC’s representative to the Backbone Mountain TAC for those bird mortality studies.

What came out of the 2004 mortality studies was what is now known as the “Shoenfeld Estimator” for calculating bird and bat fatalities at wind farms.  An internet search for “Shoenfeld Estimator for birds” produces many articles that relate to this important mathematical formula that Peter developed. Several of those articles give credit to WV Highlands Conservancy for allowing the use of the bird fatality estimator developed by Peter Shoenfeld.  And today several environmental consultants, including the giant environmental consulting firm West Inc. Inc., use the Shoenfeld Estimator for calculating bird mortalities at wind energy facilities nationwide, including at the Beech Ridge wind facility in Greenbrier County, WV.

If you want to read more about the Shoenfeld Estimator go to  Warning:  the beginning and ending parts make sense to anyone.  The middle part is all formulas; unless you have made it through at least a year or calculus the middle part will leave your head spinning.