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Best Practices for a Bird-Friendly Building
(modified from City of Toronto's rating system)

1. Glass Treatment

Extent of building design that will provide visual cues or barriers to birds and reduce dangers of glass transparency and reflections:
MINIMUM 95% of all facade areas up to thirty-six (36) feet above grade and above green roof, roof garden or landscaped deck shall have a threat factor of fifteen (15) or less [as defined by the most current American Bird Conservancy's Bird Collision Deterrence rating]; including but not exclusively these high danger areas:
  • Lobbies/atriums with interior lighting at night/early morning hours
  • Lobbies/atriums with interior greenery that is visible from the outside
  • Glass that is proximal to external greenery
  • Areas that trap birds between two or three sides of glass/windows such as an alley, alcove, corner of a building, area above a skylight/atrium, etc.
  • Glass"passageways" that appear to be areas that birds could "fly through" to open vegetation/open space on either side
  • Glass railings, windscreens, skywalks, linkways
DESIRED 95% of all facade areas up to thirty-six (36) feet above grade and above green roof, roof garden or landscaped deck shall have a threat factor of fifteen (15) or less; and

At least 60% of all facade areas above the first thirty-six (36) feet shall have a threat factor of fifteen (15) or less [as defined by the most current American Bird Conservancy's Bird Collision Deterrence rating]

OPTIMAL/BEST PRACTICE All building facade areas will have a threat factor of fifteen (15) or less [as defined by the most current American Bird Conservancy's Bird Collision Deterrence rating]
Type of glass treatment/design:
MINIMUM During spring and fall migration implement temporary treatment of transparent and reflective glass with decals, paints, films at a density pattern of two inches or less apart; or provide elements mounted on the building exterior that provide a visual and physical barrier in front of the glass including but not restricted to:
  • a. Secondary facades, shutters, sunshades, louvers with elements which shall be spaced such that openings have a size no more than 9 inches high and 9 inched wide with depth of the elements equal to the spacing or;
  • b. meshes, grids, netting, screens, shades with opening of not more than 2 inches by 2 inches
OPTIMAL/BEST PRACTICE Permanent treatment of transparent glass with UV coatings/films or frosted/fritted patterns using a density pattern of two inches or less apart, or permanent installation of elements mounted on the building exterior that provide a visual and physical barrier in front of the glass including but not restricted to:
  • a. Secondary facades, shutters, sunshades, louvers with elements which shall be spaced such that openings have a size no more than 9 inches high and 9 inched wide with depth of the elements equal to the spacing or;
  • b. meshes, grids, netting, screens, shades with opening of not more than 2 inches by 2 inches


2. Exterior Lighting

MINIMUM During Migration season:
  • No use of the following types of exterior lighting: mercury vapor, searchlights, upward-directed and aerial laser
  • All exterior must be downward shielded
  • Exterior building lighting that is unnecessary for safety, building entrances, and circulation shall automatically shut off between 11 p.m and 7 a.m.
OPTIMAL/BEST PRACTICE Year-round:
  • No use of the following types of exterior lighting: mercury vapor, searchlights, upward-directed and aerial laser
  • All exterior must be downward shielded
  • Exterior building lighting that is unnecessary for safety, building entrances, and circulation shall automatically shut off between 11 p.m and 7 a.m.


3. Building Operations

Interior greenery:
MINIMUM All Internal greenery that could be visible from outside shielded from view or removed during spring and fall migration
OPTIMAL/BEST PRACTICE No interior greenery that could be visible from outside of glass treated with density pattern of less than two (2) inches apart or shades drawn to shield view of interior greenery year-round
Interior lighting
MINIMUM Interior lighting sensor controls must be in accordance with the IEC Code. Occupant sensor lighting must be maximimzes. All other interior lighting must have time-switch controls with manual overrides allowing the reduction of lighting load by at least fifty persent. The use of task of lighting to accommodate a limited number of users after hours should be maxamized.

All interior lobby/ground flor lighting (including but not limited to: display lights, signage, video screens) shall be down-sheilded, dimmed, extinguished or blocked from egress to the exterior between 3 am to 7 am during spring and fall migration.

Cleaning operations that would require interior lighting shall be scheduled outside the hours of 3 am to 7am during spring and fall migration

OPTIMAL/BEST PRACTICE Year-round application of the above interior lighting requirements


4. Site Design

MINIMUM During Migration season:

a. Drain any pools/foutains that are directly below glass facades

b. cover ground level ventilation grates to create a porosity no greater than 3/4" by 3/4" or 1 1/2" x 3/8"

OPTIMAL/BEST PRACTICE No exterior pools, fountains proximal to glass facade areas:, or

No ventilation grates within five (5) feet of glass facades or ventilation grates with a porosity no greater than 3/4" by 3/4" or 1 1/2" by 3/8"



Chicago Bird Collision Monitors




Chicago Bird Collision Monitors (CBCM) is an all volunteer bird conservation project that operates under the auspices of
the Chicago Audubon Society.


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