Towerkill

Communications towers that are lighted at night for aviation safety may help reduce bird collisions caused by poor visibility, but they bring about a second, even more deadly mechanism for mortality.

[5] In a 25-year study of bird mortality at the 1,010-foot (310 m) tower at Tall Timbers Research Station near Tallahassee, Florida, US, kills occurred nearly every night from mid-August through mid-November.

Moderate numbers of migrating birds were killed under perfectly clear skies, but the toll increased markedly with overcast conditions.

[citation needed] Wind turbines represent a much smaller threat to birds, due to being much lower in number and lacking guy wires.

[citation needed] Overall, as of 2010, wind turbines were estimated to cause about one-tenth of a percent of all unnatural bird deaths in the United States each year.

[8][better source needed] A 2013 survey of published studies estimated that the total number of bird kills for all single-pole turbine wind farms in the United States was 140,000 to 328,000 per year.