Bird Strike: Nearly 1,000 Migratory Birds Die After Hitting Chicago Building in Single Night

A bird strike involving migratory birds struck a Chicago building in the city's downtown area in one single night in early October. It resulted in the deaths of several hundred members of the flock.

According to reports earlier this week, almost 1,000 birds died after colliding into the exterior glass windows of the building. The incident occurred as more than a million birds were migrating over Illinois that time ahead of the upcoming winter season in December.

Although the exact reason for the mass bird window collision remains unclear, several reports indicate that poor weather conditions and pollution during that time disrupted the migratory process of the birds.

The said factors are in addition to the fact that tall buildings evidently get in the path of migrating birds. Related incidents have been reported in Chicago before and in other parts of the United States in previous years.

Bird Strike at Chicago Building

The bird strike occurred last week, where at least 961 birds died after hitting the Chicago building's glass windows. At 3:40 a.m. on October 5, the migrating songbirds were part of an approximately 1.49 flock hovering above Cook County, Illinois, where Chicago is located.

In the days leading to October 5, inclement weather, including heat and strong winds, halted the bird migration process in the region. Members of the Chicago Bird Collision Monitors announced that its teams found hundreds of injured avians in downtown Chicago.

North American Bird Migration

Bird migration is a natural global phenomenon. Yet, the success of this process varies depending on a region's season, weather, climate, and other anthropogenic factors. In North America, a flock flying in the north moves to the west, while a flock flying in the south shifts toward the east.

Avian migration in the North American skies occur each spring and fall seasons, with billion of bird species on the move above Canada and the US. The North American bird migration includes four flyways called:

• Atlantic Flyway
• Mississippi Flyway
• Central Flyway
• Pacific Flyway

What Causes Bird Window Collisions?

One might think that bird strike, involving building windows, seems strange and rare. However, these incidents occur every year and are more common than previously thought. In fact, this phenomenon is not a mystery at all but is raising concern especially if it involves mass bird deaths.

The U.S. Fish and Wildlife Service (FWS) explains that birds can collide with glass when they see natural mirror reflections of the environment such as clouds, sky, or trees in the glass itself. In addition, the avians can also see plants through windows and may collide with the material when they are attracted to landscaping or interior lights, according to the FWS.

Many birds that seem to be unaffected by the window collision can succumb and die from their internal injuries later, the US wildlife government agency adds.