I don't know how, but I've eaten here 3 times and each time gotten a table by the window - and never asked for it. I consider it my special pixie dust. I love it there! The last time, the table next to us had a giant bird come visit them. Unfortunately the woman at the table was afraid of birds, so it was pretty entertaining (it's like the bird just knew).
If you don't get a table by the window, you can go by the windows during your meal to see the animals. I don't mind when people come by our table, as long as they respect our space. We've never had a negative encounter with other guests sneaking by our table, just be respectful.