above> the chicago skyline is illuminated by, in part, its buildings on march 30, 2019. (chris sweda/chicago tribune)
birds do fly at night, so going dark reduces the chances of them being lured by the glow, only to smash into glass. most building owners comply.
chicago has long aimed to be a friendlier milepost for migrating birds. since 1995, conservationists and building managers have collaborated on a voluntary program to turn off decorative outdoor lights on downtown buildings after 11 p.m. birds do fly at night, so going dark reduces the chances of them being lured by the glow, only to smash into glass. most building owners comply.
still, the birds come and they die. as many as 1 billion birds are killed in building collisions each year. chicago, located along a major migratory highway, ranks no. 1 in the united states for deaths in both spring and fall, according to a new report by the cornell lab of ornithology.
two reasonable proposals, one in chicago and one in the u.s. house, would make the winged journey less deadly.
the chicago ordinance brought by ald. brian hopkins would require certain new construction to limit the use of glass from ground level to 36 feet or employ etched or frosted glass to avoid inviting reflections of sky or water. nonessential outdoor lights would be automatically turned off between 11 p.m and sunrise. the law would apply to newly built large-scale buildings, not homes or residential buildings with six units or less.
this effort is supported by bird friendly chicago, a coalition of groups including the chicago audubon society, and by chicago architect jeanne gang. the house bill, introduced by u.s. rep. mike quigley of chicago, would apply similar rules to federal buildings nationwide.
not all developers welcome the potential restrictions. but the chicago ordinance doesn’t demand costly retrofitting — it addresses only new construction and significant renovations, when bird-friendly features can be considered at the planning stage. builders might consider that the startling thud of a creature colliding with a window isn’t pleasant for tenants, nor is stepping over the tiny corpses of colorful songbirds in the morning.
apple made national news, not the kind it wanted, in 2017 when its glassy new store on michigan avenue at the chicago river drew birds to their deaths. it soon agreed to dim lights overnight. the same year, northwestern university invested in safety film for its sparkling new lakefront kellogg school of management global hub after its bird body count ratcheted up. sterling bay’s plan for the riverside lincoln yards development includes bird-friendly design.
there are other ways to help. at cornell, researchers can predict the heaviest migration periods down to days and weeks by using radar and weather data. this opens up the possibility for narrowly timed, targeted controls on light pollution and other killers, including wind turbines.
bird populations face other threats, including climate change and habitat loss, that are much harder to solve than lethally transparent windows. no one set out to build perfect bird death traps, but expanses of reflective glass have turned out to be just that. giving winged creatures a helping hand is the right response.