Artificial light from buildings confuses and traps birds, almost always with deadly results. The photo above is a three month collection in Toronto; it totals over 1,000 birds of 89 species. The Fatal Light Awareness Program estimates that in North American alone, at least 100 million birds—mostly low-flying songbirds, die each year in collisions with man-made structures. Glass windows—baffling to birds both day and night—are the biggest contact killers, while disoriented birds may simply exhaust themselves trying to exit the city maze.

We’ve lit up the night as if it were an unoccupied country, when nothing could be further from the truth. Of all the pollution we face, light pollution is perhaps the most easily remedied.

[NGeo]