Because nobody thought that any prisons would try to escape especially with the freezing waters and shark infested waters
Robert Porter Keep was born in 1844.
Robert Porter Keep died in 1904.
Birds are covered in feathers
No, birds will just land on it.
You can keep birds from getting trapped in bird netting by removing the netting or using a color of netting that the birds can see.
Possibly you meant "How do the birds keep warm . . ."? As for why they keep themselves warm, it is to stay alive.
budgies
You can keep myna birds, parrots, canary, finches, caiques, and quite a few others.
birds
Check the local hardware store for a plastic owl. This will keep birds away. No poison too.
so that their baby's will develop properly , if your told its to keep them warm its wrong , ( birds sit on the eggs to keep them warm).