So this got me to do a quick read on owl drinking…

Owls don’t typically drink, though they can if they want to or need to due to excessive heat or lack of food.

Their water requirements are typically achieved just through eating. While eating their food whole does capture a decent amount of water, metabolism releases hydrogen atoms that combine with oxygen in the body to produce what is called “metabolic water.”

While mammals usually only generate enough metabolic water to flush out our urea, making our urine, birds are much more efficient at producing metabolic water, and they also don’t urinate, they release the uric acid directly. That is the white part of a bird poo. Both of these factors allow birds to generate their own water supply sufficient to sustain them under normal circumstances.