This is so much fun :D
Let's assume 1,000,000 towers and 10,000,000 birds are killed by the towers every year.
Hmmmm
5 billion birds create how many new birds each year reduced by 10 million birds that die as a result of the 1 million towers that benefit Man?
Seems like a good trade to me - 1,000,000 towers for Man; 10 million out of "X" billion birds born each year scarified for the benefit of Man.
I don't have a problem with those numbers assuming the correctness of the assumptions for the purpose of this discussion.