I checked again and yeah, it's more like 9.5 million square miles, so an average of more like 370 bird deaths per square mile, per year. But now that I know that includes chickens and turkeys, and Mexico and Greenland and the Bahamas, it's OK.
What's up with comms towers? High-voltage AM antennas are not that abundant anymore. Are birds getting cooked close to high-power transmitters? Shot to avoid interference with crucial military infrastructure? Is 5G real?