I believe this is an "unauthorized copy of a Takahashi bird", as the Takahashi's never used screws to attach the pin to the bird, but rather used push pins, and some were signed "KT" as Cleio alluded to. This info was taken directly from Julia Carroll's "Collecting Costume Jewelry #303" book, which has a lengthy description of several pages of Takahashi birds, and also makes for very interesting reading.
If this were a Takahashi bird, it would be sold for $100 - $200 here on eBay, but since it is a reproduction, although it is still worth something, that amount is only a smaller percentage of the value of the Takahasi bird. Also, to sell it properly, you will have to disclose that it is a reproduction.
