Do you need waterproof binoculars?

Do you need waterproof binoculars? That depends on many things.

How much time do you spend on the water or near water? Is your birding time mostly from a canoe? If so, yes you need waterproof birding binoculars.

Do you spend more time in the desert watching birds? Then maybe being waterproof is not as important as being shockproof, so when you drop them on the rocks they do not get serious damage. 

Speaking from experience, I have fallen out of a canoe while wearing my binoculars more than once.  Not always my fault. But I wear them INSIDE my vest now.