Leaking bird bath

We have a stone, could be concrete, bird bath and today I noticed it is leaking. I cannot see a crack. Is there anything I can do to fix it? It's about eight years old.

 

No idea, but, any chance of a photo?

 

There are paints that work as a sealant - at least over here there are. They are used in cellars to stop leaks. Perhaps you can find one of these?

 

Like Lori said you could use a sealant, I have used something similar called Ronseal damp seal before on my shed/toilet walls, inside and out, it's not brilliant but it stops it penetrating to some extent

 

Thank you all very much for pointing me in the right direction. I'll look into your suggestions and let you know how I get on.
This photo of the birdbath is from the last garden.