Appendix E1: Post-construction monitoring formulas

Scavenger correction factor

Proportions of carcasses remaining after each search interval are pooled to calculate an overall scavenger correction (Sc) factor:

Sc = (nvisit1 + nvisit2 + nvisit3) ÷ (nvisit0 + nvisit1 + nvisit2)

Sc is the proportion of carcasses not removed by scavengers over the search period

nvisit0 is the total number of carcasses placed

nvisit1 – nvisit3 are the numbers of carcasses remaining on visits 1 through 3

Searcher efficiency

Searcher efficiency (Se) can be calculated for each searcher as follows:

Se = (number of test carcasses found) ÷ (number of test carcasses placed − number of carcasses scavenged)

The number of turbines that each individual searches will vary so it will be necessary to calculate a weighted average that reflects the proportion of turbines searched by each searcher. The weighted average or overall searcher efficiency can be calculated as follows:

Seo = Se1(n1/T) + Se2(n2/T) + Se3(n3/T)

Seo is the overall searcher efficiency

Se1 and 2 and 3 are individual searcher efficiency ratings

N1 and 2 and 3 are number of turbines searched by each searcher

T is the total number of turbines searched by all searchers

Proportion of area searched

Proportion of area searched (Ps) is calculated as follows:

Ps = actual area searched ÷ πr2

r = 50 metres

Corrected mortality estimates

The minimum estimated mortality (C) is calculated as follows:

C = c / (Se0 × Sc × Ps)

C is the corrected number of fatalities

c is the number of carcasses found

Se0 is the weighted proportion of carcasses expected to be found by searchers (overall searcher efficiency)

Sc is the proportion of carcasses not removed by scavengers over the search period

Ps is the proportion of the area searched.

Other notes and considerations

Should additional mortality be found based on supplemental monitoring (for example, associated with SWH) and using the same standard protocols, this mortality should be included in the calculation of mortality rates.

Appendix E2: Sources of information on bats, birds, significant wildlife habitat, and wind power

The following sources of information may be useful in providing data to assist with records review (go to section C2):

Appendix E3: Bird and Bat References

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American Wind Wildlife Institute. 2017. Wind turbine interactions with wildlife and their habitats: a summary of research results and priority questions. Washington, D.C. 12p.

Arnett, E.B. 2006. Preliminary evaluation of the use of dogs to recover bat fatalities at wind energy facilities. Wildlife Society Bulletin 34:1440-45.

Arnett, E. B., D.B. Inkley, D.H. Johnson, R.P. Larkin, S. Manes, A.M. Manville, J.R. Mason, M.L. Morrison, M.D. Strickland and R. Thresher. 2007. Impacts of wind energy facilities on wildlife and wildlife habitat. Wildlife Society Technical Review 07-2. 52p.

Arnett, E.B., K. Brown, W.P. Erickson, J.K. Fiedler, B.L. Hamilton, T.H. Henry, A. Jain, G.D. Johnson, J. Kerns, R.R. Kolford, C.P. Nicholson, T.J. O’Connell, M.D. Piorkowski, and R.D. Tankersley Jr. 2008. Patterns of bat fatalities at wind energy facilities in North America. Journal of Wildlife Management 72:61-78.

Arnett, E.B., M. Schirmacher, M.M.P. Huso and J.P. Hayes. 2009. Effectiveness of changing wind turbine cut-in speed to reduce bat fatalities at wind facilities. An annual report submitted to the Bats and Wind Energy Cooperative. Bat Conservation International. Austin, Texas, USA.

Arnett, E. B., R.M.R. Barclay and C.D. Hein. 2013. Thresholds for bats killed by wind turbines. Frontiers in Ecology and the Environment 11:171.

Arnett, E.B., E.F. Baerwald, F. Mathews, L. Rodrigues, A. Rodrıguez-Duran, J. Rydell, R. Villegas-Patraca and C.C. Voigt. 2016. Impacts of wind energy development on bats: a global perspective. Pages 295–323 in C.C. Voigt and T. Kingston, editors. Bats in the Anthropocene: conservation of bats in a changing world. Springer International Publishing, New York, New York, USA.

Betts, B.J. 1998. Roosts used by maternity colonies of silver-haired bats in Northeastern Oregon. Journal of Mammalogy 79:643-650.

California Energy Commission and California Department of Fish and Game. 2007. California Guidelines for Reducing Impacts to Birds and Bats from Wind Energy Development. California Energy Commission, Renewables Committee, and Energy Facilities Siting Division, and California Department of Fish and Game, Resources Management and Policy Division. CEC-700-2007-008-CMF.

Campbell, L.A., J.G. Hallett and M.A. O’Connell. 1996. Conservation of bats in managed forests: use of roosts by Lasionycteris noctivagans. Journal of Mammalogy 77:976-984.

Clerc, J., M. Huso, M. Schirmacher, M. Whitby and C. Hein. 2025. Ultrasonic deterrents provide no additional benefit over curtailment in reducing bat fatalities at an Ohio wind energy facility. PLoS One 20:0318451.

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Environment Canada – Canadian Wildlife Service (EC-CWS). 2007. Recommended protocols for monitoring impacts of wind turbines on birds. 33 p.

Estellés-Domingo, I. and P. López-López. 2025. Effects of wind farms on raptors: a systematic review of the current knowledge and the potential solutions to mitigate negative impacts. Animal Conservation 28:334-352.

Friedenberg, N.A. and W.F. Frick. 2021. Assessing fatality minimization for hoary bats amid continued wind energy development. Biological Conservation 262:109309.

Garvin, J.C., J.L. Simonis and J.L. Taylor. 2024. Does size matter? Investigation of the effect of wind turbine size on bird and bat mortality. Biological Conservation 291:110474.

Gilmour, L.R.V., M.W. Holderied, S.P.C. Pickering and G. Jones. 2020. Comparing acoustic and radar deterrence methods as mitigation measures to reduce human-bat impacts and conservation conflicts. PLoS ONE 15:0228668..

Good, R.E., G. Iskali, J. Lombardi, T. McDonald, K. Dubridge, M. Azeka and A. Tredennick. 2022. Curtailment and acoustic deterrents reduce bat mortality at wind farms. Journal of Wildlife Management 86:22244..

Hayes, M. A., L.A. Hooton, K.L. Gilland, C. Grandgent, R.L. Smith, S.R. Lindsay, J.D. Collins, S.M. Schumacher, P.A. Rabie, J.C. Gruver and J. Goodrich-Mahoney. 2019. A smart curtailment approach for reducing bat fatalities and curtailment time at wind energy facilities. Ecological Applications 29:01881.

Horn, J.W., E.B. Arnett and T.H. Kunz. 2008. Behavioural responses of bats to operating wind turbines. Journal of Wildlife Management 72:123-132.

Kerns, J., W.P. Erickson and E.B. Arnett. 2005. Bat and bird fatality at wind energy facilities in Pennsylvania and West Virginia. pp. 1-38. In Arnett, E.B., Technical Editor. Relationships between bats and wind turbines in Pennsylvania and West Virginia: an assessment of bat fatality search protocols, patterns of fatality, and behavioural interactions with wind turbines. A final report submitted to the Bats and Wind Energy Cooperative. Bat Conservation International, Austin, Texas, USA.

Kalcounis-Ruppell, M.C., J.M. Psyllakis and R.M. Brigham. 2005. Tree roost selection by bats: an empirical synthesis using meta-analysis. Wildlife Society Bulletin 33:1123–1132.

Korner-Nievergelt, F., R. Brinkmann, I. Niermann and O. Behr. 2013. Estimating bat and bird mortality occurring at wind energy turbines from covariates and carcass searches using mixture models. PLoS ONE 8:67997.

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Kunz, T.H., E.B. Arnett, B.M. Cooper, W.P. Erickson, R.P. Larkin, T. Mabee, M.L. Morrison, M.D. Strickland and J.M. Szewczak. 2007. Assessing impacts of wind-energy development on nocturnally active birds and bats: a guidance document. Journal of Wildlife Management 71:2449-2486.

Lacki, M.J. and J.H. Schwierjohann. 2001. Day-roost characteristics of northern bats in mixed mesophytic forest. Journal of Wildlife Management 65:482-488.

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Loeb, S.C., T.J. Rodhouse, L.E. Ellison, C.L. Lausen, J.D. Reichard, K.M. Irvine, T.E. Ingersoll, J.T.H. Coleman, W.E. Thogmartin, J.R. Sauer, C.M. Francis, M.L. Bayless, T.R. Stanley and D.H. Johnson. 2015. A plan for the North American Bat Monitoring Program (NABat). US Department of Agriculture Forest Service, Southern Research Station. General Technical Report SRS-208. 100p.

Loss, S.R., T. Will and P.P. Marra. 2013. Estimates of bird collision mortality at wind facilities in the contiguous United States. Biological Conservation 168:201-209.

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Owen, S.F., M.A. Menzel, W.M. Ford, J.W. Edwards, B.R. Chapman, K.V. Miller and P.B. Wood. 2002. Roost Tree Selection by Maternal Colonies of Northern Long-eared Myotis in an Intensively Managed Forest. Published by USDA Forest Service, Newtown Square, PA.

Psyllakis, J.M. and R.M. Brigham. 2006. Characteristics of diurnal roosts used by female Myotis bats in sub-boreal forests. Forest Ecology and Management 223:93–102.

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Schaub, T., R.H.G. Klaassen, C. De Zutter, P. Albert, O. Bedotti, J-L Bourrioux, R. Buij, J. Chadoeuf, C. Grande, H. Illner, J. Isambert, K. Janssens, E. Julius, S. Lee, A. Mionnet, G. Müskens, R. Raab, S. van Rijn, J. Shamoun-Baranes, G. Spanoghe, B. Van Hecke, J. Waldenström and A. Millon. 2024. Effects of wind turbine dimensions on collision risk of raptors: a simulation approach based on flight height distributions. Science of the Total Environment 954:176551. https://doi.org/10.1016/j.scitotenv.2024.176551.

Smallwood, K.S., D.A. Bell, S.A. Snyder and J.E. Didonato. 2010. Novel scavenger removal trials increase wind turbine–caused avian fatality estimates. Journal of Wildlife Management 74:1089–1097.

Taylor, D.A.R. 2006. Forest Management and Bats. Bat Conservation International. 16p.

Watt, R.W. and M.C. Caceres. 1999. Managing for snags in the boreal forests of Northeastern Ontario. OMNR. Northeast Science and Technology. Technical Note-016. 20p.

Weschler, M. and L. Tronstad. 2024. Wind energy and insects: reviewing the state of knowledge and identifying potential interactions. PeerJ 12:18153.

Whitby, M.D., M.R. Schirmacher and W.F. Frick. 2021. The State of the Science on Operational Minimization to Reduce Bat Fatality at Wind Energy Facilities. A report submitted to the National Renewable Energy Laboratory. Bat Conservation International. Austin, Texas. 99p.

Whitby, M.D., M.T. O’Mara, C.D. Hein, M. Huso and W.F. Frick. 2024. A decade of curtailment studies demonstrates a consistent and effective strategy to reduce bat fatalities at wind turbines in North America. Ecological Solutions and Evidence 5: 12371.

Zimmerling, J.R., A.C. Pomeroy, M.V. d’Entremont and C.M. Francis. 2013. Canadian estimate of bird mortality due to collisions and direct habitat loss associated with wind turbine developments. Avian Conservation and Ecology 8:10.

Zimmerling, J.R. and C.M. Francis. 2016. Bat mortality due to wind turbines in Canada. Journal of Wildlife Management 80:1360-136