How do those microwave transmitter lines work? Do they need to be empty from station to station? Does a bird flying break the connection? Would a drone block it

How do those microwave transmitter lines work? Do they need to be empty from station to station? Does a bird flying break the connection? Would a drone block it? I read the high frequency trading firms use own towers to transmit messages. Could a rogue competitor fly a drone/kite to "block the view" and break the connections?