Wild Republic Audubon Bird Purple Martin II. Wild Republic's Audubon Birds Series is now in its 12th year and still going strong. This is undoubtedly due to the tremendous popularity of Birding, the second most popular US hobby.These little plush birds are 6 to 8 inches long and sing their own particular song when squeezed.They are made by Wild Republic in partnership with the Audubon Society. The Purple Martin bird sound recordings are made by the Cornell Lab of Ornithology. Item number 21381.