digitS' :
That stinky water is probably caused by hydrogen sulfide. It is an indicator of anaerobic decomposition. Botulism is an anaerobic bacterium . . .
Er, there are a LOT of different causes of stinky water in the world. H2S would not be my top bet as long as this is water from a potable...
With all due respect diana, I dunno... the reason that botulism in wild birds is typically associated with water is that wetland mud contains (for at least part of the year) exactly the oxygen-free conditions that botulism spores need in order to flourish.
Unless she is doing something really...