ants in the window hummingbird feeder

Now this is perfectly understandable, ants being a constant battle with nectar feeders, but…. this window hummingbird feeder has a built-in ant moat.
So I proceeded to ask: “Is the moat filled with water” and she said “yes”. “Has the moat always been filled with water?” I asked, rather puzzled. After explaining that ants can’t swim, if the moat were consistently filled with water, this would be impossible. Ants just can not cross a body of water. So, my belief is that the water must have evaporated from the moat – it’s really the only logical explanation.
By the way, this is a great little window hummingbird feeder because it allows for full view of birds. It can also be used as a seed feeder during colder months, attracting more feathered friends for close-up viewing!