I've got 3 in my back yard and they are all used heavily. I refill them with clean water every evening when I water my flowers. I usually have a wide variety of birds, squirrels and even chipmunks in them. One is tall and the other two are short, about 12-15 inches off the ground. The chipmunks can hop into those. I've even seen a raccoon drinking from one of them. I love to watch all the wildlife in them but I think the cats love it more. Also I have several bird feeders in the yard I keep filled with food which helps to attract all the birds and critters too.