HomeMy WebLinkAboutOrdinance 62-O-26 Amending Title 4 Chapter 24 Bird Friendly Building Design (1)
09/28/2026
62-O-26
AN ORDINANCE
Amending City Code Title 4, Chapter 24 “Bird Friendly Building Design”
WHEREAS, this building ordinance has been created to address the role
of the City of Evanston’s built environment in the annual loss of up to one billion birds
due to glass collisions in the United States; and
WHEREAS, birds provide valuable and important ecological services; and
WHEREAS, the City of Evanston has recorded approximately two
hundred eighty (280) species of resident and migratory birds; and
WHEREAS, millions of birds migrate through the Evanston and Chicago
corridor each spring and fall; and
WHEREAS, reducing light pollution has been shown to reduce bird deaths
from collision with windows; and
WHEREAS, the Building & Development Services Division and Bird
Friendly Evanston have modified a set of criteria originally developed by the Chicago
Department of Planning and Development, Chicago Bird Collision Monitors, Chicago
Audubon Society and other interested departments and individuals to encourage
inclusion of bird friendly design strategies into development projects to reduce bird
collisions and death; and
WHEREAS, Title 4, Chapter 24 of the Evanston City Code establishes
bird-safe standards for building construction to reduce bird mortality from circumstances
that are known to pose a high risk to birds and are known to be “bird hazards”. The
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purpose of these controls is to ensure new construction is bird safe and to decrease
existing bird hazards over time.
NOW, THEREFORE, BE IT ORDAINED BY THE CITY COUNCIL OF
THE CITY OF EVANSTON, COOK COUNTY, ILLINOIS, THAT:
SECTION 1: Title 4, Chapter 24, of the Evanston City Code, as amended,
is hereby further amended in its entirety and replaced with the following:
CHAPTER 24 – BIRD FRIENDLY BUILDING DESIGN
4-24-1. PURPOSE.
The purpose of this chapter is to establish bird-safe standards for building construction
to reduce bird mortality from circumstances that are known to pose a high risk to birds in
the built environment.
4-24-2. DEFINITIONS.
Building Collision Threat
Rating (BCTR)
The calculated threat rating of a facade zone based on
the material threat factor (MTF) of each of its component
materials proportional to the amount of area of each
material in the façade zone. A lower threat rating
indicates a lower risk of collisions.
Fly-Through Condition A building design feature providing line of sight from one
glazed portion of the exterior façade to another, such as
glass corners, greenhouses, skyways, glass walkways,
bus shelters, guard shelters, and entryways.
High Risk Features Components and areas of a building facade or structure
that have been identified as particularly susceptible to
bird collisions, including: all exterior fly-through
conditions, railings, awnings, windbreak/windscreen
panels, acoustic barriers, ground-level building links,
elevated walkways, bus shelters, guard shelters, and
exterior decorative panels or signage.
Interior Landscaping Plants, either artificial or natural, located inside a building
with visibility to the exterior through the building façade.
This does not include landscaping visible through the
roof plane (i.e. skylights).
Material Threat Factor
(MTF)
An index developed by the American Bird Conservancy
(ABC) to assign scores that provide a relative measure
of birds’ ability to see and avoid patterned glass and
other materials. A lower score indicates a material that is
more visible to birds than a higher score. The lowest
MTF (1) indicates a solid, non-transparent, non-reflective
material such as masonry or stucco. The highest MTF
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(100) indicates the most hazardous materials, which are
highly reflective and/or highly transparent.
Zone 1 This zone includes façade areas up to sixty (60) feet
above grade, façade areas up to sixteen (16) feet above
green roofs, roof gardens, or landscape/amenity decks,
and façade areas up to three (3) feet above the height of
mature vegetation.
Zone 2 This zone includes all building façade areas not included
in the definitions of Zone 1 or High Risk Features.
4-24-3. APPLICABILITY
The Bird Friendly Building Design Ordinance shall apply to the following:
(A) Planned developments.
(B) New commercial, industrial, and multifamily construction projects not within the
scope of the International Residential Code (IRC) as adopted by the City.
(C) Renovation of any of the above building types that includes the replacement of
50% or more of the exterior glazing, whether installed simultaneously or in
planned stages.
4-24-4. BUILDING COLLISION THREAT RATING CALCULATION.
For the purposes of this chapter, the Building Collision Threat Rating (BCTR) for each
zone shall be calculated as follows:
(A) Identify the material threat factor (MTF) for each façade material.
(B) Determine the square footage of façade area (FA) occupied by each material.
(C) To determine the façade factor (FF) for each material type, multiply the
material threat factor (MTF) of the material by the square footage of façade
area (FA) it occupies (MTF x FA = FF).
(D) To determine the Building Collision Threat Rating (BCTR), add together the
façade factor (FF) for all material types and divide that sum by the total façade
area (Sum FF ÷ Total Façade Area = BCTR).
4-24-5. BUILDING FAÇADE
Projects shall adhere to one or both of the following building façade compliance
options.
(A) Compliance Option A
1. Projects shall comply with the requirements in each of the three
following areas, as defined in Section 4-24-2: High Risk Features, Zone
1, and Zone 2.
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i. High risk features shall have a material threat factor (MTF) of
thirty (30) or less.
ii. Zone 1 areas shall have a building collision threat rating (BCTR)
of fifteen (15) or less.
iii. Zone 2 areas shall have a building collision threat rating (BCTR)
of thirty (30) or less.
(B) Compliance Option B
1. Glazed areas shall be protected with one or more of the following
permanent external features:
i. Secondary facades, shutters, sunshades, or other permanent
features greater than 2 inches in depth (excluding any support
framework, standoffs, mounting accessories, etc.) with openings
such that a 9-inch diameter sphere cannot pass through any
opening. The distance from the face of the glass to the edge of
the feature shall not exceed the depth of the feature.
ii. Meshes, netting, screens, or other permanent features less than
2-inches in depth with openings such that a 2-inch diameter
sphere cannot pass through any opening.
4-24-6. EXTERIOR LIGHTING.
(A) All exterior light fixtures shall be full cutoff fixtures to minimize up-lighting
conditions.
(B) Buildings must have controls to extinguish exterior and decorative lighting
above the first floor of buildings at 11 p.m. each evening and leave lights off
until daylight from March 15 to June 15 for the spring migration, and again
from August 15 to November 15 for the fall migration.
(C) The following types of exterior lighting are prohibited:
1. Mercury vapor luminaires
2. Searchlights
3. Sky beams
4. Upward-directed fixtures
5. Aerial lasers
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4-24-7. EXTERIOR FEATURES.
(A) At grade ventilation grates within twenty (20) feet of glass façades shall have
openings such that a 3/4-inch diameter sphere cannot pass through any
opening.
(B) Exterior pools and fountains shall not be located closer than twenty (20) feet to
glazed façade areas.
4-24-8. HISTORIC PRESERVATION.
The terms of this Chapter shall neither limit nor prohibit the applicability of Title 2,
Chapter 8 (“Historic Preservation"), of the City Code, as amended, to any construction
or renovation project. Exemptions to the requirements of this Chapter may be granted
by the City’s Building Official for a building or structure of historical significance that is a
designated landmark or located within a local historic district.
4-24-9. SUBMITTAL REQUIREMENTS.
At the time of application for a building permit, documentation demonstrating
compliance with this Chapter, including, but not limited to the following, shall be
provided:
(A) Include the following statement on the architectural drawings: “All exterior
materials, components, glazing and lighting have been evaluated for
compliance with the City of Evanston Bird Friendly Building Design ordinance.”
(B) Dimensioned Elevations
1. Building Façade Compliance Option A. Indicate façade Zones 1 and 2.
Indicate location of high-risk features. Indicate façade materials on the
drawings and include a Material Threat Factor table showing all façade
materials.
2. Building Façade Compliance Option B. Indicate secondary façade, shutter,
sunshade, mesh, netting, and screen systems on elevations. Provide
detailed specifications for each system to demonstrate compliance with
this chapter.
(C) Material Threat Factor (MTF) and Building Collision Threat Rating (BCTR)
calculation table. Include table on the drawings for each zone (High Risk, Zone
1, and Zone 2).
(D) Exterior Lighting. Provide light fixture schedule and fixture specifications for
exterior lighting to demonstrate compliance with this Chapter.
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4-24-10. COMPLIANCE.
Upon completion of the project, the designer of record shall submit a letter attesting to
the project’s compliance with this Chapter. Compliance with this Chapter shall be
required prior to the issuance of a certificate of occupancy.
SECTION 2: All ordinances or parts of ordinances in conflict herewith are
hereby repealed.
SECTION 3: If any provision of this ordinance or application thereof to any
person or circumstance is held unconstitutional or otherwise invalid, such invalidity shall
not affect other provisions or applications of this ordinance that can be given effect
without the invalid application or provision, and each invalid provision or invalid
application of this ordinance is severable.
SECTION 4: The findings and recitals contained herein are declared to be
prima facie evidence of the law of the City and shall be received in evidence as
provided by the Illinois Compiled Statutes and the courts of the State of Illinois.
SECTION 5: This ordinance shall be in full force and effect thirty (30) days
after its approval and passage.
Introduced:_________________, 2026
Adopted:___________________, 2026
Approved:
__________________________, 2026
_______________________________
Daniel Biss, Mayor
Attest:
_______________________________
Stephanie Mendoza, City Clerk
Approved as to form:
_______________________________
Alexandra B. Ruggie, Corporation Counsel
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