>        In the past, potty training birds was in widespread disfavor
>    among serious aviculturists, for although it is easiest to train
>    a parrot to defecate on verbal command, this method is
>    dangerous. Some birds are so eager to please that they will
>    incur life-threatening kidney damage waiting for that verbal
>    command. This becomes an issue if the owner is ill or injured or
>    must go out of town. A forgotten instruction to command the bird
>    to defecate has proved fatal on numerous occasions.
I have to jump on this one. I honestly do NOT believe this can occur.
I think it's an avicultural "urban legend".
Think about it. How many HUMANS can "hold it" at will until they incur
internal damage without "having an accident"? Not anybody *I* know, not
even the best potty-trained adult humans. When the bladder/bowel is
full, it WILL eventually empty, even if there is no "correct" or
appropriate available place to empty it. This happens on a daily basis
to well-trained dogs and cats all over the world when not allowed access
to their regular potty places for whatever reasons.
I seriously doubt that ANY bird is going to become that willing to
please ANY human that they could override their natural bodily functions
long enough to damage themselves. I am certain that the bird's body
would force an excretion to occur long before physical damage could be
done by holding feces/urates too long.
I think that even if a bird was taught to only "go" on verbal command,
if not told to "go", sooner or later he'd break training against his
will--when ya gotta go, ya just gotta go! 
--Kathy
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