Also, why dont off shore windmills operations build off existing unused structures like out of commission oil rig platforms? Assuming the biggest additional cost is building the same as land structure but without hundreds of feet of additional structure for new off shore windmill structures?

Edit: im admittedly uneducated on this, but feel like if

Birds are not something that can simply be avoided. They are far more complex than bugs, and bugs are still a problem (while they exist in substantial numbers anyways, which might then solve the bird "problem" too!).

There is nothing at airports that dissuade birds from flying except airplanes. Full stop. There is no magic pill.

... ok ok maybe there are specific deterrents at specific airports, but that does not a norm make.

Also, the kinds of birds that are going to fly by off shore wind mills are not going to be the same species as birds flocking around airports. It's not only a problem that does not have a magical solution, but a wholly separate problem to begin with.