I have never seen this, and I work with microwave towers nearly every day. The 'drum like cover' is called a radome, and it's primary purpose is to reduce the

I have never seen this, and I work with microwave towers nearly every day. The 'drum like cover' is called a radome, and it's primary purpose is to reduce the wind loading of the microwave dish. It also serves to protect the usually sensitive feedhorn inside the dish, keep out bird nests, ice, water, etc... The common cause of bird deaths around radio towers is collision, not RF energy. In Florida it is very common to see osprey nests build on/in/around towers. Microwave dishes are a common location because they provide a large horizontal surface to support the nest. See Wikipedia article 'Towerkill' https://en.wikipedia.org/wiki/Towerkill https://en.wikipedia.org/wiki/Towerkill