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Best Practices for a Bird-Friendly Building

For new construction, additions and renovated portions of building facades:

1. Glass Treatment

Objective is to provide visual cues or physical barriers between birds and transparent or reflecitve glass.
The following areas shall have a Bird Collision Threat Rating (BCTR) of fifteen (15) or less, as defined by the most current American Bird Conservancy Bird Collision Deterrence ratings:
  • 1. At least 95% of facade areas up to sixty (60) feet above grade;
  • 2. At least 95% of facade areas up to sixty (60) feet above green roofs, roof gardens, or landscape/amenity decks;
  • 3. Atleast 60% of facade areas higher than sixty (60) feet above grade;
  • 4. At least 95% of glass in glass railings, awnings, windbreak panels, acoustic barriers, skywalks, walkways, bus shelters, guard shelters, exterior decorative panels, and other ground level features.
Exception: In lieu of providing the calculated facade BCTR, protect the above designated areas of glass with any of the following:
  • 1. Secondary facades, shutters, sunshades, or other permanent features greater than 2 inches in thickness (excluding any support framework, standoffs, mounting accessories, etc.) iwht openings such that a 9-inch diameter sphere cannot pass through any opening. Distance from the face of glass to the edge of the feature shall not exceed the thickness of the feature.
    Example: If a 6-inch-deep vertical sunshade system is to be installed, the sunshade cannot be located more than 6inches away from the face of the glass and cannot have any openings larger than a 9-inch diameter sphere.
  • 2. Meshes, netting, screens, or other permanent features less than 2-inch thickness with openings such that a 2 inch diameter sphere cannot pass through any opening.
For existing buildings:
  • 1. use the above recommendations to retrofit glass facade areas, or
  • 2. during spring and fall migration implement temporary treatment of transparent and reflective glass areas with paints, films or mounted elements (screens, netting, external shade, banners, cords, etc.) as visual and physical barriers in front of glass areas using a density pattern of 2 inches or less apart


2. Exterior Lighting

Year-round or during migration seasons March 15 to June 15 and August 15 to November 15:
  • No use of the following types of exterior lighting: mercury vapor, luminaires, searchlights, upward-directed, and aerial laser
  • All exterior lighting fixtures shall be full-cutoff.
  • 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. Exterior features:

Exterior pools and fountains shall not be located closer than twenty (20) feet to glass facade areas.
Existing exterior pools and fountains less than twenty (20) feet from glass facade areas will be drained during migration seasons March 15 to June 15 and August 15 to November 15.

Ventilation grates within twenty (20) feet of glass facades shall have openings such that a 3/4-inch diameter sphere cannot pass through any opening.



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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