Heavy Bombers - Try This
Heavy bombers cannot land on a spike nor do they like trip wires just above the runway.
So what you need is a 3" long upwards point from the pivot of your Windex to discourage masthead attackers, though I have seen a crow using my Windex as a merry-go-round! They also pecked one cup off the anemometer as I guess it disturbed their sleep.
For the boom one needs two short sticks with a length of fishing line tied between. One stick pushes into the sheave box on one side at the boom end poking upwards and then the line takes one turn completely round the mast and back to the second stick in the other side of the sheave box. The line, being taut, then runs along each side of the sail cover and is 2-3" above the sail cover.
The spreaders are your problem as mine are not seen as parking/roosting spots. I guess a length of fishing line between the shrouds, again 2" to 3" above should do it.