The Piasa Bird is Native American mythical creature, so seems an unlikely choice for a North-East English glass manufacturer to incorporate into a glass pattern. The Piasa Bird glass is not in any known Sowerby Pattern books, and is unlike any other glass they were known to be manufacturing at the time. Additionally, the Piasa Bird glass rarely comes up for sale in England. The majority of time the glass is advertised for sale in North America, suggesting the manufacturer was most likely based in the USA.

However, the glass is often advertised as being made by Sowerby of England. I believe this misattribution is the result of the following book entry.

Piasa Bird

After reviewing a copy of Cyril Manley’s Decorative Victorian Glass, I can say this pattern is English, probably by Sowerby.  Manley shows it in a ruby glass with applied decoration, but the feet and design above them can’t be mistaken for anything else.  In opalescent glass, it is found in both white and blue but certainly vaseline was made.  Shapes are bowls, vases, and several whimsey shapes, all footed, from the same mould.

Standard Encyclopedia of Opalescent Glass (2011) by Mike Carwile, p.107

Having also reviewed Cyril Manely’s Decorative Victorian Glass (1988), I have been unable to find a single piece of ruby coloured pressed glass, with applied decoration. The only three-footed piece of ruby coloured pressed glass by Sowerby is the dolphin bowl, which really can’t be mistaken for the Piasa Bird.