Capital Design Guidelines


Urban development is putting more and more pressure on birds, and it has come to light that collision with glass surfaces on and around buildings is now the second-most common human-related cause of bird mortality. It is estimated that, in North America, as many as one billion birds are killed by colliding with windows each year.

Birds are unable to recognize glass as an impermeable surface. As a result, birds may strike windows when they attempt to fly through glass to vegetation or habitat on the other side, or when they try to reach the habitat mirrored in the glass. Collisions with glass affect all birds regardless of species, sex, health or age, amplifying the negative impacts of this issue on bird populations.

The bird collision problem is exacerbated by light emanating from buildings and outdoor lighting at night. Birds use visual cues to help them navigate along their migration routes. Light from buildings and outdoor light fixtures can attract birds into urban areas and disorient them, causing them to change their flight patterns, which can lead to exhaustion, emaciation or death. This situation also increases birds’ likelihood of colliding with windows during daylight hours.


The goal of these guidelines is to reduce bird–building collisions on NCC lands and on federal buildings and lands in the National Capital Region.

Policy Statement

The NCC will apply bird-safe design guidelines to all projects on NCC lands, and all projects on federal buildings and lands in the National Capital Region that involve glass or lighting and are subject to federal land use, design and transaction approval, as well as to all projects that involve landscaping adjacent to buildings or other structures containing glass or reflective surfaces.

Applicable Law

Light that reflects off or radiates from buildings is considered a contaminant under the Environmental Protection Act (EPA) of Ontario, and allowing such light emissions, if they harm or kill species at risk, contravenes the Species at Risk Act (SARA). Also, the Migratory Birds Convention Act (MBCA) prohibits the incidental take of migratory birds and the deposit of substances harmful to birds in areas frequented by migratory birds. Owners or managers of buildings where the design results in the death of or injury to birds may be found guilty of an offence under federal or provincial laws, as applicable, if they fail to take reasonable preventative measures to reduce the risk their buildings present to birds.


The following guidelines draw from current bird-friendly standards and are in line with the Canadian Standards Association’s standard on Bird-Friendly Building Design (A460:19), which is Canada’s first national standard on bird-safe design for buildings, and the City of Ottawa’s Bird-Safe Design Guidelines. These guidelines were developed in consultation with a core team of staff from various NCC divisions, FLAP Canada and Safe Wings Ottawa. In addition to standards for building site, architectural, lighting and landscape design, these NCC-specific guidelines also contain recommendations for heritage buildings.

1 Overall Site and Building Design

Overall site and building design for new buildings and structures must limit risks to bird safety.

The first step toward limiting bird-window collisions is to ensure that building site design does not pose inherent risks to birds. While windows are important features that allow building occupants to feel a connection to nature, it is important to anticipate where birds will be in relation to the glass in the structures on-site. Certain types of building design and glass-containing architectural features are inherently risky for birds. However, with thoughtful design and window placement, buildings can be designed to reduce the risks to birds, while also maintaining connections with nature and maximizing energy efficiency.

  • 1

    Overall Site and Building Design

    • 1.1

      To the extent possible, and consistent with NCC master plans, building should be limited in existing natural areas, including migratory bird routes, shorelines, green spaces, wetlands and ecological corridors, to minimize impacts on birds and other wildlife.

    • 1.2

      Where buildings are located in proximity to a natural area, the buildings and windows should be oriented in a way as to limit reflection of habitat (trees, shrubs, hedges, water and wetlands) on glass surfaces and to limit fly-through conditions, whereby birds can see the habitat on the other side of a building through two panes of glass.

    • 1.3

      All buildings should be designed to minimize bird collisions by minimizing or eliminating the use of the following design elements:

      • large expanses of undistinguished glass, including spandrel glass, or other reflective material, such as polished stone or steel (ideally, the total surface area of glass should be no more than 40 percent of the overall facade);
      • parallel or angled glass elements where birds can see through to the other side of the building (common in linkways, lobbies, corners, alcoves, atriums and alleyways);
      • open-topped atriums, which can trap birds;
      • glass balustrades;
      • transparent wind and sound barriers;
      • free-standing glass architectural elements.

2 High-risk Glass Treatment

High-risk glass must be treated with high-contrast visual markers to render it bird-safe.

The properties of glass that pose a risk to birds are transparency (because birds do not recognize the glass as a physical barrier and try to fly through it) and reflectivity (because birds see habitat reflected in the glass). Both issues must be addressed in order to reduce the risk that glass surfaces pose to birds.

  • 2

    High-risk Glass Treatment

    • 2.1

      In the areas listed below, a minimum of 90 percent of all glazed (glass) surfaces must be treated with the application of high-contrast visual markers:

      • up to the greater of 16 m above grade or the height of the surrounding vegetation at maturity (which may be up to 45 m in the National Capital Region);
      • on a green roof, up to the greater of 4 m above the surface of the green roof/rooftop garden or the height of the surrounding vegetation at maturity.
    • 2.2

      In the areas listed below, 100 percent of all glazed (glass) surfaces must be treated with the application of high-contrast visual markers:

      • all glazed surfaces that create fly-through conditions, such as parallel glass, glass balustrades and glass corners, which must be treated for 5 m in each direction;
      • all glazed surfaces up to the greater of the first 16 m above grade or the height of the surrounding vegetation at maturity, where the structure is located directly adjacent to a shoreline, woodlot or wetland.
    • 2.3

      Visual markers must be applied to the first surface (outside) of the glass, and must be at least 4 mm in diameter and spaced no further than 50 mm apart.

    • 2.4

      Non-vision glass (such as spandrel glass and privacy glazing) should be treated with a full surface treatment on the first surface that renders the glass visible to birds (opaque and non-reflective).

    • 2.5

      Visual markers applied according to the specifications in subsections 2.1 and 2.2 may consist of, but are not limited to, the following:

      • muntins, mullions or grilles (bars that divide the pane of glass),
      • grates and screens,
      • commercial films and adhesives,
      • patterns created by acid etching, silk screening or ceramic frit.

      Source: Clause 3, CSA A460:19, Bird-Friendly Building Design. © 2019 Canadian Standards Association. Please visit

3 Building-associated Structures

Building-associated structures that pose a risk to birds must meet bird-safe criteria.

Some structures associated with buildings, including ventilation grates, free-standing glass elements and antennas, may pose a risk to birds and must adhere to the following bird-safe criteria.

  • 3

    Building-associated Structures

    • 3.1

      Glass structures associated with buildings, such as glass railings or balustrades and free-standing glass architectural elements, including wind and sound barriers, must be treated as per guideline 2.2 above.

    • 3.2

      Outdoor art installations with expanses of transparent glass or highly reflective surfaces should be avoided or treated as per guideline 2.2 above.

    • 3.3

      All ventilation grates must have a porosity of no more than 20 mm × 20 mm or 40 mm × 10 mm.

    • 3.4

      Vents and pipes with an opening greater than 400 mm² must be covered with a screen or cap.

    • 3.5

      The use of guy wires should be avoided, and antennas should be consolidated into one tower.

4 Building-integrated Structures

Building-integrated structures may be used to reduce bird collisions, but must meet bird-safe criteria.

Some building-integrated structures can be effective at deterring bird collisions while adding to the architectural design detail of the building and increasing building energy efficiency. Building-integrated structures may be used to deter bird collisions, provided they follow the guidelines below.

  • 4

    Building-integrated Structures

    • 4.1

      When building-integrated structures are used to reduce bird collisions, they must be permanently fixed to the building and non-movable. If removable or movable structures, such as exterior shades, are used, they must be used in concert with the glazing treatments specified in Section 2.2.

    • 4.2

      Shades and louvres used to deter bird collisions must be parallel or angled to the glass surface, not more than one metre from the parallel pane of glass, have gaps no greater than 50 mm, and have a solid-to-void ratio of 50 percent or more.

    • 4.3

      Screens or grilles used to deter bird collisions must have a maximum gap of 19 mm x 19 mm, and must be installed at least 50 cm from the glass, on the exterior.

    • 4.4

      Exterior, stationary shutters used to deter bird collisions must have gaps no larger than 50 mm.

      Source: Clause 3, CSA A460:19, Bird-Friendly Building Design. © 2019 Canadian Standards Association. Please visit

5 Building Interior Lighting

Building interior lighting should be limited from sunset to sunrise.

Interior lighting from buildings draws birds into urban areas where they are at an increased risk of colliding with windows. Light from high-rise buildings emanating up into the sky can attract and disorient birds, causing them to congregate around buildings in urban areas and become exhausted. Reducing lighting in buildings from sunset to sunrise helps to alleviate this problem.

  • 5

    Building Interior Lighting

    • 5.1

      In cases where interior lighting is visible from the outside of the building, it should be reduced from sunset to sunrise using any or all of the following:

      • installing motion detectors and/or timers to automatically extinguish lights in unoccupied spaces;
      • making task lighting options available to reduce lighting in unoccupied spaces;
      • installing blackout shades or blinds that can be drawn at night;
      • installing dimmer switches to reduce light intensity in occupied spaces.

6 Outdoor Lighting

Outdoor lighting on NCC lands should be dark-sky-compliant.

Outdoor lighting directed up at the sky contributes to sky glow (the brightness of the night sky in a built-up area as a result of light pollution) and may pose a threat to birds. These guidelines should be applied to all lighting on NCC lands, whether in relation to a building or not. Lighting projects completed under the Capital Illumination Plan will be reviewed on a case-by-case basis to weigh various factors, and should follow the guidelines below to the extent possible.

  • 6

    Outdoor Lighting

    • 6.1

      In general, outdoor lighting, whether associated with a building or not, should follow dark-sky-compliant best practices according to the following criteria.

      • Lighting should be on only when required for nighttime visibility, wayfinding, or to highlight elements of heritage, historical, cultural, architectural or social value (this can be achieved through the use of motion sensors and automatic timers).
      • Only the areas that require lighting for nighttime visibility, wayfinding, or to highlight elements of heritage, historical, cultural, architectural or social value should be lit (this precludes the use of flood lighting).
      • To reduce over-lighting and limit blue light transmissions, all outdoor lights should have a colour temperature of no more than 3,000 Kelvin (ideally, LED lighting should be amber, not white).
      • Full cut-off fixtures should be used to limit spill light (light that falls outside the area which is meant to be lit).
    • 6.2

      Where non-dark-sky-compliant lighting is required for special events or light shows, the impact of lighting on birds should be limited by avoiding the use of uplights and by not using spotlights, lasers or searchlights, especially during migratory bird seasons (March to May and August to October).

    • 6.3

      Where rooftop, façade and monument architectural illumination are required under the Capital Illumination Plan or to showcase heritage characteristics, it should be directed downward toward the structure and should be turned off or, at a minimum, dimmed, between 11 pm and 6 am.

7 Landscaping Around Buildings

Landscaping around buildings should be designed to reduce the risk of bird collisions with windows.

The landscaping adjacent to a building has an impact on bird-window collisions by affecting how many birds will be in the direct vicinity of the building and how much vegetation is reflected in the windows of the building. While it is important and encouraged to provide habitat for birds in urban areas, and it is not generally necessary to deter birds from buildings that have been made bird-safe; there are some landscaping guidelines that increase bird safety. The following landscaping guidelines should always be used in concert with bird-safe building design guidelines.

  • 7

    Landscaping around Buildings

    • 7.1

      Landscaping adjacent to buildings and structures should be designed to minimize reflections of vegetation in windows and other reflective surfaces. (Trees and shrubs planted within one metre of glass surfaces, even if they do not produce reflections in the glass, have not been shown to be effective at preventing bird collisions in all cases. Where trees and shrubs are planted within one metre of glass surfaces, these areas should be monitored for bird collisions using a protocol such as in Annex D of the CSA standard on Bird-Friendly Building Design and/or treated as per the guidelines in Section 2.2, as necessary.)

    • 7.2

      Landscape designs that channel birds toward windows, such as tree-lined walkways leading toward windowed entrances, should be avoided.

    • 7.3

      Species known to attract birds, such as those with abundant nectar, seeds or fruit, should be avoided within 20 metres of glass or reflective surfaces, even if those surfaces have been treated with high-contrast visual markers.

    • 7.4

      Bird feeders and other features, such as bird baths, should be located less than 50 cm OR more than 9 m from glass surfaces.

    • 7.5

      Features with open water, such as fountains, ponds, stormwater retention infrastructure and engineered wetlands, should be located in areas where they will not be reflected in windows or other reflective surfaces. If this is not possible, the bird collision mitigation strategies in Section 2.2 must be implemented.

    • 7.6

      Indoor plants and landscaping features should be located so they are not visible through building windows. Where plants are visible from outside the building, the bird collision mitigation strategies in Section 2.2 must be implemented.

    • 7.7

      Existing vegetation must NOT be removed for the sole purpose of reducing the threat of bird collisions. Where bird collisions are a problem, the bird collision mitigation strategies in Section 2.2 must be implemented.

8 Heritage Characteristics

Heritage characteristics must be considered in conjunction with bird-safe design.

When making any intervention in heritage and historic buildings and sites (i.e. buildings and sites with heritage value and character-defining elements), decisions should be guided by the Standards and Guidelines for the Conservation of Historic Places in Canada. All proposed bird collision mitigation strategies should be seen in the context of the heritage elements present within the building and site. As each building and site is unique, each intervention must be dealt with on a case-by-case basis, with careful consideration for the integration of these bird collision mitigation strategies into the heritage context.

In many cases, the bird collision mitigation strategies in sections 2.2 to 2.7 can be implemented without impacting heritage considerations. The following guidelines should be applied to bird-safe design projects on existing buildings where heritage designations may apply.

  • 8

    Heritage Characteristics

    • 8.1

      Before applying bird collision mitigation strategies, all documentation with respect to the heritage values of the historic place, including any heritage designations, must be reviewed to determine if there are heritage conservation considerations that must be implemented on-site.

    • 8.2

      If a heritage designation exists, appropriate heritage experts must be engaged in all stages of review, selection and approval of potential bird collision mitigation strategies and must approve the selected strategies.

    • 8.3

      All character-defining elements of a heritage-designated building and site must be identified BEFORE any approved bird collision mitigation strategies are implemented, to ensure that these elements are appropriately conserved during project implementation.

    • 8.4

      Where character-defining elements may pose a risk to birds, a qualified bird collision mitigation expert should be engaged in a site assessment to determine which elements pose a lethal, high, moderate or low risk to birds. Those elements that are determined to pose the highest risk to birds (lethal or high) should be treated with bird collision mitigation strategies.

    • 8.5

      Where character-defining elements are determined to pose a high or lethal risk to birds, bird collision mitigation strategies that do not require changes to the building (such as those in sections 2.5 an 2.7) should be implemented first, and monitored for their effectiveness using a protocol such as in Annex D of the CSA standard on Bird-Friendly Building Design. If the risk to birds is not mitigated by these interventions, the guidelines in sections 2.2 to 2.4 and 2.6, or other appropriate and effective bird collision mitigation strategies, as verified by a bird collision mitigation expert and approved by heritage experts, should be implemented.


  1. Machtans, C. S., C. H. R. Wedeles, and E. M. Bayne (2013). “A first estimate for Canada of the number of birds killed by colliding with building windows.” Avian Conservation and Ecology 8(2):6.
  2. Canadian Standards Association (2019). CSA A460:19, Bird-Friendly Building Design. CSA Group.
  3. City of Markham (2014). Bird Friendly Guidelines Visit Website
  4. City of Ottawa (2020). Bird-Safe Design Guidelines. Download PDF
  5. International Dark-Sky Association (no date). Outdoor Lighting Basics.