How to keep birds away from my fruit trees?

I have a beautiful guava tree in my back garden. It is bearing fruit nowadays and LOTS OF IT. The branches are heavy with guavas.

However evreytime I go to collect some fruit, the ripe ones are always bird eaten. They are so clever they don’t go near the non ripe ones. And any fruit that is even half done, they’ve pecked away at.

Please help. I’d love to be able to enjoy some of my own fruit. How can I stop these birds from getting to the ripe stuff?