This instrument comprises:
1) 7 pigeon whistles, purchased by Jeffrey Boswall in Chengdu 成都 in 1986. One was 'purchased in Peking in 1984 by Anthony Galsworthy, who describes it as "old"'.
2) A wooden, 2-part ‘twirling gadget on which pigeon whistles may be tested’. Purchased by Jeffrey Boswall in Chengdu in 1986.
A handwritten note by Jeffrey Boswall explains: 'Whistle for attachment to the tail feathers of a domestic pigeon. When the bird flies a sound is created.'