E1. Potential effects of wind power projects on birds and bats

Wildlife and their habitats are important to Ontario’s biodiversity and the people of the province. Wind power has the potential to negatively impact wildlife species directly and indirectly by causing mortality and habitat impacts, including displacement and disruption of movement corridors. With significant efforts to monitor and evaluate these relationships, application of knowledge on proper siting and mitigation can reduce the risk of negative environmental effects significantly.

Research and monitoring indicate birds and bats may be disproportionately impacted by wind power.

The purpose of this part E of this Guide is to outline requirements to reduce risks to birds and bats by promoting proper siting of wind power projects, or to support conservation of these species through operational mitigation and mortality monitoring when key habitats cannot be avoided.

E1.1 Potential effects on birds

Bird mortality at wind projects is generally lower than for bats and is lower than from other bird mortality sources (for example, collisions with windows, collisions with power/transmission lines, cat predation). Monitoring at wind projects in Ontario indicates that relatively low numbers of bird fatalities occur at wind power facilities. Known current bird mortality levels at existing wind power projects are not considered a sustainability concern for most of Ontario’s bird populations.

Turkey vulture is a species regularly killed by wind turbines in Ontario. This is related to their soaring and searching behaviour, lower maneuverability relative to other bird species and wind/thermal dynamics that may result in greater activity in the areas with turbines. Turkey vultures have increased in number and expanded their range in Ontario. They are relatively abundant in Southern and Central Ontario. While wind power impacts are not currently a concern for the population, mortality at turbines cannot be discounted due to their life history (that is, long-lived species with low reproductive potential). Black vulture is a similar species whose range is naturally expanding into Ontario from the south. It is often found in association with turkey vultures and will be susceptible to mortality at wind facilities.

While mortality impacts are generally not significant, poorly sited wind power projects can have a significant impact on birds through collision mortality (for example, with turbine blades, guy wires, meteorological towers) and indirectly through habitat disturbance and behavioural changes (for example, displacement from breeding or migration areas). In addition, increasing height and size of turbines may increase mortality risk for birds. The single most important factor to minimize negative impacts to birds is appropriate siting to avoid migration corridors and areas with high density of birds (for example, feeding areas, colonial nesting sites and staging areas).

In cases where all or part of a project has been sited in an area that results or would result in significant bird displacement from habitat or mortality at the project or single turbine scale, there are limited options to mitigate impacts. Shutting down turbines during critical periods where mortality is known to be high may reduce risk but with potential for significant impacts to energy production. Alternative approaches and emerging or new technologies can also be considered in an effort to reduce bird mortality.

E1.2 Potential effects on bats

Data suggests that greater than 1 million bats die each year at wind power facilities across North America. Most of these bat fatalities are caused by bats colliding with moving turbine blades, and generally not with stationary structures (for example turbine towers, transmission structures, guy wires, and more). Barotrauma (internal haemorrhaging), caused by rapid air pressure reduction near moving turbine blades, has also been found to be a source of bat mortality. Fatalities are highest during late summer high activity periods and autumn migration, particularly on nights with low wind speeds. Across North America, it is estimated that most bat fatalities occur from mid-July through September. Long-distance migratory bats (that is, hoary bat, eastern red bat, silver-haired bat) typically comprise the majority of bat fatalities in Ontario, but other species are impacted.

Bats may also be indirectly affected by wind power projects through habitat loss or fragmentation during the construction and/or operation of a facility. Bat habitats may be affected by turbines placed near bat swarming and hibernation sites, breeding or roosting habitats, or migration stopover areas. Improper siting that affects bat habitat also increases mortality risk.

Mitigation establishing minimum cut-in speeds are known to be effective at reducing bat mortality, but the benefits may vary based on a range of factors. Additional work continues to evaluate smart mitigation methods that are engaged only when bats are detected in the area. Generally, operational mitigation can be implemented in a way that significantly reduces bat mortality, while minimizing loss of energy production.

E1.3 Cumulative effects

With proper siting and mitigation strategies, the risk of potential impacts from wind power on birds and bats can be reduced at the project scale. However, each additional wind power project may affect habitat availability and use and will result in increased mortality of birds and bats. In addition, migratory behaviour of many birds and some bat species may expose these species to multiple wind facilities over the course of a year. Cumulative effects of each additional project must be considered, along with implementing further restrictions when necessary to reduce or eliminate population level impacts, particularly for species like migratory bats whose numbers may have already been reduced by mortality at wind power projects.

E2. Natural heritage assessment for birds and bats

Part C of this Guide outlines requirements for completing the 3 stages of an NHA, which include a records review, a site investigation and an evaluation of significance. These requirements apply to bird and bat wildlife habitat present at the project location or within 50 or 120 metres of any part of the project location. Go to part C for more information.

Selecting the proper location for the project is generally the most important consideration to minimize potential effects to birds and bats and their habitats. All applicants must undertake an NHA to consider bird, bat and their habitat-related information relevant to the proposed project location. It is also important to consider potential project location relative to landscape features in the area that may increase the risk associated with bird and bat mortality at a wind power project (for example, forested island habitats, isolated habitats, peninsulas, shorelines).

Ideally, selection of a project area and individual turbine locations within a project site should be an iterative process. As bird and bat habitat within and adjacent to a potential project area are being reviewed, the applicant should consider adjusting the project footprint to avoid bird and bat habitats if possible. As discussed in section E3 of this Guide, this will have implications for mitigation and monitoring requirements.

In addition to specific nesting habitats identified as SWH, Ontario’s Fish and Wildlife Conservation Act, 1997 (FWCA) specifically protects the nests and eggs of bird species that aren’t protected federally under the Migratory Birds Convention Act, 1994 (MBCA). The only exceptions are the nests and eggs of American crow, brown-headed cowbird, common grackle, house sparrow, red-winged blackbird and starling. Section 133.1 of O. Reg. 665/98 (Hunting) made under the FWCA enables a person carrying out a renewable energy project to remove a known nest of provincially protected bird species identified through the NHA process without additional authorization if it cannot be avoided during construction or operation of the wind project. In this case, a nest identified as part of the NHA in the application package can be removed once the project is approved, but not during the active nesting season when young are present. The person must also be carrying out the renewable energy project in accordance with a renewable energy approval under part V.0.1 of the Environmental Protection Act. Authorization may be required from MNR to remove any nest that was not identified in the NHA process. These authorizations require review and approval and will not be granted during the active nesting season. Applicants should inquire with Environment and Climate Change Canada for guidance on the nests of migratory bird species protected under the MBCA, and with the MECP for the nests/eggs of species protected under the Species Conservation Act (SCA).

To further reduce risks to bats and birds, applicants should consider avoiding habitat areas not specifically defined as SWH that are important to birds and bats in siting decisions (for example, foraging habitat, movement corridors, woodlands where bat roosts may be present). Some of these other habitat features may be identified by a qualified person through other aspects of the NHA.

E3. Wind power risk mitigation framework for birds and bats

Similar to other natural features, for wind power projects, if any bird or bat SWH was identified at or within 120 metres of any part of the project location following completion of the NHA, applicants have two options: (a) re-locate the project outside of the natural feature and its 120 metre adjacent lands, or (b) complete additional studies, plans and reports to identify, assess and mitigate negative environmental impacts.

This section describes requirements under section 23.1 of the Regulation and additional requirements specific to birds and bats regarding the EIS and EIS Report required under section 38(2)(a) of the Regulation. This includes bat and bird habitat related requirements and bird mortality mitigation requirements.

A bird/bat EEMP is required if the project is located within bird or bat SWH or the 120 metre adjacent lands to bird or bat SWH. As described in section C4 of this Guide, bird or bat SWH includes the boundary of an important bird area. An applicant has the following options:

  1. Locate project outside of bird or bat SWH and its 120 metre adjacent lands:
    • if the project is located more than 120 metres outside bird or bat SWH, the applicant does not need to prepare an EEMP with respect to bats, birds, or their habitats (which means no habitat mitigation requirements and no post-construction mortality mitigation and monitoring)
    • in this case, bird or bat SWH includes candidate bird or bat SWH that the applicant treats as significant (go to section C4.1 of this Guide)
    • this approach is based on information that indicates locating wind projects outside key habitat significantly reduces risks to birds, and for bats when combined with mortality mitigation requirements required under the SCA
    • SWH and IBAs boundaries may change over time and the decision by an applicant to take this approach will be based on boundaries at the time the NHA is completed
    • applicants are encouraged but not required to consider implementing mortality monitoring at a sample of turbines and, depending on the results, to consider implementing operational mitigation measures as needed to reduce the risk of mortality
  2. Locate project within bird or bat SWH and/or its 120 metre adjacent lands:
    • if the project is proposed within bird or bat SWH or within the adjacent lands to bird or bat SWH, the applicant must prepare a bird/bat EEMP in accordance with mitigation and monitoring requirements described in section E3.1 of this Guide

Applicants are responsible for all applicable requirements related to bird and bat species at risk under the SCA and its regulations, which includes bat mortality mitigation and potential monitoring requirements.

E3.1 Requirements for locating project within bird or bat SWH and/or its 120 metre adjacent lands

If the project will proceed within 120 metres of bat or bird SWH, the applicant must follow an approach with greater requirements. While locating a project within significant bat and bird habitat is strongly discouraged, this approach recognizes it may be difficult to avoid bat and bird SWH in some cases. The general requirements for this approach are described in further detail in the sections of this Guide that follow.

E3.2.1 Environmental impact study (EIS)

An EIS must be prepared following the procedures outlined in part D of this Guide. The EIS must address direct and indirect effects related to the affected bird and/or bat habitats, as the case may be, describing:

  • any negative environmental effects of the project to the habitat
  • mitigation measures and specifically how the measures will address any negative environmental effects to SWH and IBAs
  • additional habitat mitigation to be implemented if initial results are unsuccessful

IBA boundaries may change over time. Mitigation for habitat within an IBA that may be affected should be based on habitat within the IBA at the time the EIS is being completed.

The significant wildlife habitat technical guide together with the significant wildlife habitat mitigation support tool provide SWH mitigation considerations and options for renewable energy projects. General approaches to minimizing potential negative effects to bird and bat SWH include:

  • careful consideration of project or specific turbine location to avoid SWH, IBA or other areas recognized as important
  • construction at less sensitive times of the year to avoid disturbing wildlife, their key life processes (for example, nesting) and habitats
  • restoration of habitat disturbed during construction

E3.2.2 Bird/bat environmental effects monitoring plan

An environmental effects monitoring plan with respect to birds and bats (EEMP) must be prepared if the project is located within 120 metres of bat or bird SWH. The EEMP must include the following components:

  • operational mitigation plan to reduce bird mortality risk
  • post construction bird mortality monitoring plan
  • additional specific operational mitigation measures that will be implemented to reduce bird mortality below thresholds exceeded (for example, periodic shutdown of turbines causing significant mortality)
  • how bird and bat habitat mitigation will be monitored to measure the success of the mitigation actions identified in the EIS

Bat mortality mitigation and monitoring is required under EEMP but these requirements are to be addressed by complying with the same obligations under the SCA.

E3.2.3 Post-construction operational mitigation to reduce bird mortality risk

The EEMP must describe post construction mitigation measures that will be implemented to reduce bird mortality risk and seek to prevent the project from exceeding bird mortality thresholds. The mitigation plan must include additional strategies that will be implemented if bird mortality thresholds at a project are exceeded (for example, shutting-down specific turbines causing the greatest mortality during critical periods).

Mortality monitoring results must be compiled and estimates updated throughout the required monitoring period. If a project exceeds any mortality threshold, additional mitigation measures must be applied immediately. Further measures must be added until bird mortality falls below the threshold(s) exceeded. Measures in place at that time must be maintained.

E.3.2.4 Post-construction bird mortality monitoring

Effective post-construction mortality monitoring is critical to assessing the impacts of projects constructed within or adjacent to key habitats.

Monitoring must be conducted at all turbines for projects >10 turbines. For projects ≥10 turbines, initial bird mortality monitoring may use a probability-based design that draws from a representative sample of at least 30% of turbines (minimum of 10 turbines) from throughout the project area. Once a wind facility is fully operational, at least 3 consecutive years of post-construction bird mortality monitoring must be completed. If no bird mortality threshold is exceeded, no further mortality monitoring is required but periodic (for example, once every 3 years) checks are recommended to ensure conditions haven’t changed resulting in an increase in bird mortality.

Any time a project exceeds any project-scale bird mortality threshold, monitoring of bird mortality must be conducted at an increased sample of turbines (that is, increased sampling intensity) across the project area. If a turbine specific mortality threshold is exceeded, additional monitoring must be initiated to include all other turbines within the same natural feature (for example, habitat, ridgeline). The increased monitoring must continue until further mitigation measures reduce bird mortality below all mortality thresholds for 3 consecutive years. This helps ensure there aren’t unknown impacts at un-monitored turbines and may allow a project to reduce mortality below thresholds by introducing operational mitigation at specific turbines or in specific parts of a wind facility area.

Once bird mortality has been reduced below all thresholds for 3 consecutive years, additional mitigation measures must be maintained, but no further monitoring is required. Periodic mortality monitoring checks are recommended to ensure conditions haven’t changed resulting in an increase in bird mortality.

The qualified person is responsible for developing the specific bird mortality monitoring protocol building on the basic requirements outlined here. The complete monitoring plan and protocol must be described in the Bird/Bat EEMP. The EEMP should make note that bat mortality mitigation and monitoring requirements are being addressed through compliance with SCA. While some basic mortality monitoring methods may apply across all projects, other aspects must be tailored to turbine size, habitat type, and more. Over time, monitoring protocols and techniques have improved. The monitoring protocol should incorporate the latest advances in methodology.

Post-construction bird mortality monitoring must include the following plans and estimates:

  • planned survey schedule at selected wind turbines
  • monitoring of scavenger/carcass removal rate
  • monitoring of searcher efficiency (that is, number of bird fatalities present that are actually detected by surveyors)
  • proportion of area searched
  • disturbance effects monitoring within SWH or an IBA boundary

Formulas for calculating variable estimates that can be used to produce a corrected mortality estimate are provided in appendix E1 of this Guide. Corrected mortality estimates should be produced and reported related to each mortality threshold (for example, birds/turbine/year, raptors/turbine/year). There are other acceptable calculation methods, including various modelling approaches that may use somewhat different monitoring variables, which can be used to produce corrected mortality estimates related to each threshold. In addition to mortalities/turbine/year, results should also be calculated and reported as mortalities/MW/year.

Other minimum requirements for post-construction monitoring effort and timing include:

  • post construction bird mortality monitoring must be conducted from May 1 through October 31, or through January 31 if the project is located in raptor wintering habitat
  • post-construction monitoring must begin on May 1 of the year that the wind power project is fully operational, or as soon as any turbine is operational if within the required monitoring period
  • monitoring should be considered beginning as early as April 1 in areas and in years where significant bird migration movements into or through the project area is expected prior to May 1
  • mortality monitoring frequency should be twice per week from May 1 to October 31 and during any additional periods where monitoring is conducted to capture mitigation of birds in the area. However, the specific frequency used in the monitoring protocol can be adjusted based on a quantitative assessment of level of mortality and carcass removal/persistence for different seasons at the site (go to Ravache et al. 2024)
  • when applicable, surveys for raptor mortality after October 31 may be restricted to the project area found within raptor wintering habitat
  • the reporting period includes all monitoring within one calendar year (that is, from January 1 to December 31)

E3.2.5 Mortality thresholds

Mortality thresholds provide a key indicator when a wind project may present a significant risk to birds. When thresholds are exceeded, projects must implement additional mitigation measures to further reduce risks. Relying on mortality thresholds requires effective monitoring of bird mortality to produce unbiased estimates, including capturing the variation in mortality that may occur under different conditions (for example, weather, timing of migration and other movements). Lack of good information on population status of some birds, along with unknowns about future scale of wind power build-out and cumulative effects, makes it challenging to establish biologically relevant thresholds. While bird mortality from wind projects is generally not as significant a concern as bat mortality and of less concern than other bird mortality factors (that is, collisions with windows, cat depredation), if poorly sited in key habitat and under certain weather conditions, bird mortality can be significant. Long-lived bird species with generally low reproductive rate (for example, raptors) have the potential to be impacted by an increase in mortality from wind turbines. The thresholds below are based on previous bird mortality thresholds for wind power mitigation in Ontario, modified based on considerations described above.

When the following levels of mortality are exceeded, projects must implement additional mitigation measures as described in the bird/bat EEMP.

  • 14 birds per turbine per year at individual turbines or turbine groups, including turkey and black vultures
  • 0.2 raptors per turbine per year across the wind power project, not including turkey and black vultures
  • 2 raptors per wind power project (<10 turbines), not including turkey and black vultures
  • a significant mortality event where a single mortality monitoring survey reveals:
    • 10 or more birds at any one turbine
    • 33 or more birds at multiple turbines