Birds don’t urinate.
Mammals remove excess nitrogen from their bodies by converting it to a dilute solution of urea, stored in the bladder. Birds convert nitrogen to uric acid ( Uric acid is the chalky white substance in bird droppings and urea which is water soluble. Uric acid is insoluble ) instead. Birds therefore don't have a urethra, and don't pee and all waste leaves via the anus.
