These birds are 5 inches of overall length. There is a hole through the entire body of the bird to slip the line through. Injection molded high impact plastic construction. These work great in daisy chains, on a bar, or in front of a lure. Adding a little commotion to your spread by rigging things with birds can sometimes draw strikes from bigeyes and yellowfin that you might not have gotten otherwise. The most popular application for bird teasers is Tuna, but they work well for mahi-mahi, marlin, and sailfish as well.