Somewhere between 5 million and 50 million migratory birds die every year from slamming into communications towers for cell phones, pagers, and radios, according to the U.S. Fish and Wildlife Service. Now, environmentalists are suing the Federal Communications Commission to force it to protect those birds. The lawsuit concerns towers that are at least 200 feet tall and located near the Gulf of Mexico, a common stopover for many species during spring and fall migrations. The suit was filed by the American Bird Conservancy, Friends of the Earth, and the Forest Conservation Council, which want the FCC to require existing towers to use warning devices (such as colored lights and high-pitched sound) to keep birds away. They also want all future tower proposals to be reviewed for likely impacts on bird populations. The affected critters include some of the nation’s most endangered songbirds — the black rail, Bell’s vireo, the golden-winged warbler, and Henslow’s sparrow.