Your brooch is a white metal a.k.a. pot metal which are most often 30's/40's, although I can tell that your piece is one of the popular knock-offs from one of the Marcel Boucher bird of paradise designs -- off hand, I believe that this one is based on his 'Jack to Martha' brooch from the early 40's. It appears that the beak tip on the right hand side is missing, as well as a portion of the tail feathers on the lower left.
Hope this helps.