how does a scarlet macaw defendre it self in front of it enemis?

First of all it will rear up and puff up it's feather to look more formidable, then it has a very large beak which can apply a pressure of 350pounds per square inch, in simpler words it can quite easily take off a human finger with one bite if it so desired.

If you had this type of defence do you feel you would be threatened by any enemy and bear in mind they are very quick and accurate.

They have large, powerful beaks which they use to defend themselves. They will bite any person or animal if provoked.