Yes FPSC really asks this type of very interesting questions.

Well I don't know its exact answer but what we can see is that they do only 'beets'. May be they don't possess kidneys at all.

Secondly, the question is "why don't we see"?

It's logical answer may be that bcoz we do not want to see bcoz question is "why we don't see" instead of "why we can't see".

Another logical answer would be that probably they do some 'invisible' peeing ..... so we don't see it bcoz after all question is not "why birds do not pee" but is "why don't we see".

Still another logical answer can be that they do peeing in very small washrooms in their nests. Since those washrooms are very small, so we cannnot see inside them. "SO WE DON'T SEE"....

Another possibility might be that they do peeing only when they find no human being around them. That's why "WE DON't SEE".

Anyway please dont be "logical" in the paper of SCIENCE.

Since I do not know it's exact answer ... so let's wait for the right answer suggested by someone.

Thanks!

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