This website has some perfect data for your analysis: http://large.stanford.edu/courses/2016/ph240/white1/

Each location is different since the bird population is changing, species are different, the placement and size of the turbines are different. Maybe you want to focus on a geographical area or a group of bird like migratory species.

 Hello Carlos.  A number of studies have been done attempting to answer if the fatalities observed at a wind farm(s) will affect a species.  This work includes red kites in Europe, bats in north america, and others.  

If you knew what bird species you wanted  to consider, you could model those bird species using demographic models, or PBR, and get an estimate of how many birds can be killed before the population begins to decline.  

We've done something similar, which you can find here:

https://www.researchgate.net/project/Wind-Energy-Impacts-Assessment-Methodology

Some of the papers and reports in this project have many citations relevant to your question.  Also, you should see the new paper by Winifred Frick

https://www.researchgate.net/publication/313930591_Fatalities_at_wind_turbines_may_threaten_population_viability_of_a_migratory_bat

Article Fatalities at wind turbines may threaten population viabilit...

Bird mortality by wind turbines varies by country and by wind turbine design. Here is the statistics in the U.S. per wind turbine (WT):

Mean = 5.25 

Upper bound = 7.35

Lower bound = 3.15

Bird mortality can be expressed per MW power produced by WT. Here is the statistics in the U.S.:

Mean = 4.12

Upper bound = 5.76

Lower bound = 2.47

You my also want to download my lecture notes on wind turbines from my ReseaechGate.net profile.

I use the above statistics in my Yale course as follows:

Khalil, Y.F. (2017). Green Energy Systems (GES). Yale University, New Haven, CT 06520 USA.

Professor Yehia Khalil, Yale University, USA

Fellow of the University of Oxford, UK

Hello Carlos. You can consult the state of the art, and specific impacts in this guidelines and reviews: 

Anderson, R., Morrison, M., Sinclair, K., & Strickland, D. 1999. Studying wind energy/bird interactions: a guidance document. Metrics and methods for determining or monitoring potential impacts on birds at existing and proposed wind energy sites. Washington, DC: National Wind Coordinating Committee.

Atienza, J.C., Martín Fierro, I., Infante, O., Valls J. & Domínguez, J. 2011. Directrices para la evaluación del impacto de los parques eólicos en aves y murciélagos (versión 3.0). SEO/BirdLife, Madrid. 117 Págs.

California Energy Commission and California Department of Fish and Game. 2007. California Guidelines for Reducing Impacts to Birds and Bats from Wind Energy Development. Commission Final Report. 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.

Canadian Wildlife Service of Environment Canada. 2006. Recommended Protocols for Monitoring Impacts of Wind Turbines on Birds. Environment Canada. Canadian Wildlife Service.

González, F., Alcalde, J. T. & Ibáñez, C. 2013. Directrices básicas para el estudio del impacto de instalaciones eólicas sobre poblaciones de murciélagos en España. SECEMU. Barbastella, 6 (núm. especial): 1-31.

Jones, G., Cooper-Bohannon, R., Barlow, K. & Parson, K. 2009. Determining the potential ecological impact of wind turbines on bat populations in Britain. Scoping and method development report. Final report. Bat Conservation Trust, University of Bristol, Bristol, UK, 158 pp.

Kunz, T. H., Arnett, E. B., Cooper, B. M., Erickson, W. P., Larkin, R. P., Mabee, T., Morrison, M.L.,  Strickland, M.D. & Szewczak, J. M. 2007. Assessing impacts of wind‐energy development on nocturnally active birds and bats: a guidance document. The Journal of Wildlife Management 71(8): 2449-2486.

Marques, A.T., Batalha, H., Rodrigues, S., Costa, H., Pereira, M. J. R., Fonseca, C.F., Mascarenhas, M. & Bernardino, J. 2014. Understanding bird collisions at wind farms: An updated review on the causes and possible mitigation strategies. Biological Conservation 179: 40-52.

National Research Council 2007. Environmental Impacts of Wind-Energy Projects. Washington, DC: The National Academies Press, 2007.

Peste, F., Paula, A., da Silva, L. P., Bernardino, J., Pereira, P., Mascarenhas, M., Costa, H., Vieira, J., Bastos, C., Fonseca, C. & Pereira, M. J. R. 2015. How to mitigate impacts of wind farms on bats? A review of potential conservation measures in the European context. Environmental Impact Assessment Review 51: 10-22.

Rodrigues, L., L. Bach, M.-J. Dubourg-Savage, J. Goodwin & C. Harbusch. 2008. Guidelines for consideration of bats in wind farm projects. EUROBATS Publication Series No. 3 (English version). UNEP/EUROBATS Secretariat, Bonn, Germany, 51 pp.

Strickland, M.D., Arnett, E.B., Erickson, W.P., Johnson, D.H., Johnson, G.D., , Morrison, M.L., Shaffer, J.A. & Warren-Hicks, W. 2011. Comprehensive Guide to Studying Wind Energy/Wildlife Interactions. Prepared for the National Wind Coordinating Collaborative, Washington, D.C., USA.

U.S. Fish and Wildlife Service. 2012. U.S. Fish and Wildlife Service Landbased Wind Energy Guidelines. U.S. Fish and Wildlife Service, Washington, D.C., USA.

Wind Turbine Guidelines Advisory Committee. 2010. Wind Turbine Guidelines Advisory Committee Recommendations. Submitted to the Secretary of the Interior through U.S. Fish and Wildlife Service on March 4. 162 pp.

Thank you very much.

If you could help me in this new topic I would highly appreciate it:

https://www.researchgate.net/post/What_avoidance_rate_should_I_use_for_nocturnal_migrant_gulls_in_relation_to_a_wind_farm_using_the_BAND_model_Collision_risk_assessment