[DoctorBeaver (OP)]

 []

[Carol-A]

"Like the reptiles, birds are primarily uricotelic, that is, their kidneys extract nitrogenous wastes from their bloodstream and excrete it as uric acid instead of urea or ammonia. Uric acid is excreted along with feces as a semisolid waste since birds do not have a separate bladder or uretral opening."

[DoctorBeaver (OP)]

Thank you, Carol. That answers the question nicely  []

[Make it Lady]

I always thought bird dirt was acidic. Long time ago when I had a rubbish car with a bad paint job. A huge bird doings left quite a mark on my bonnet. You may notice that bird dirt is runny.   

[JnA]

since birds do not have a separate bladder or uretral opening."

cloaca

it's a good word.