Not only is the subject matter on the present cup extremely rare but the extraordinary three-dimensional carving of the bird to the interior of the cup would appear to be unique. Compare with a cup in the collection of Thomas Fok with a short-tailed bird carved on the interior among branches, illustrated by the owner in Connoisseurship of Rhinoceros Horn Carving in China, Hong Kong, 1999, p. 140, no. 91.
Although the subject matter on the present cup is rare, a number of cups depicting other short and long-tailed birds are known as well as other examples carved with cockerels, phoenix and cranes are illustrated and discussed by Jan Chapman, The Art of Rhinoceros Horn Carving in China, London, 1999, pp. 185-187. A libation cup from the Edward T. Chow and Franklin Chow Collection depicting hawks was sold at Sotheby's Hong Kong, 8 April 2011, lot 2718. Another Zisheng-marked cup decorated with a cockerel on the side of the exterior, was sold at Christie's Hong Kong, 1 November 2004, lot 951.