No other shadow agate bottle appears to be published where natural inclusions form a 'calligraphic signature'.
Natural inclusions, either edited or not, suggestive of birds are fairly well recorded, though generally an agate of more yellowish tone rather than the almost 'silk canvas' grey-white stone of our example. For other examples depicting birds, see lots 69, 71 and 73 in this collection; and also Hugh Moss, Victor Graham and Ka Bo Tsang, The Art of the Chinese Snuff Bottle, The J & J Collection, Hong Kong, 1993, vol. I, p. 214, no. 127; and pp. 224-225, nos. 136 and 137