|That little green addition makes all the difference.|
I had a great spot for a feeder in my Portland house, and I spent most of last summer watching the little guys swarm around the nectar day after day after day. When I moved to Salem, I thought I had a perfect spot all picked out, as it's high up off the ground, near blooming flowers (lavender) and close to no structure a cat could get to. In short, I thought I had this whole thing all worked out.
I didn't count on the sugar ants.
The very first day I had the feeder out, a small line of ants crawled up from the ground into that feeder, and the water turned cloudy as their little bodies disintegrated. Really, really disgusting stuff.
I had read about using an ant moat filled with water (see a how-to right here), and I considered giving that a try, but the feeder is in a very windy location and I was a little worried that the cup would just blow right over before it killed any ants at all. In the end, I bought a Perky Pet ant trap. I was skeptical at first, but within one day, all of the ants on the feeder were gone and I've never seen another one come back. The birds, on the other hand, don't seem disturbed by the disk at all and they've been quite active in the early morning hours.
If you'd like to do your own feeder (you should!), check out this link.