Can we see a photo of the 'business end' of the pipe, please?
Can you be more specific about the material that was used to make the birdbath; you say ceramic and then pottery; is the bottom unglazed?
One more question please. Can you measure the length of the flange (if that is the correct word) that the pvc pipe attaches to? Is the flange part of the molded birdbath and made of the same material as the birdbath?
Sorry for so many questions.