Bluegrassmom: I am not familiar with the type of feeder you have, but having been tortured to death with hummingbird feeders over the years, I looked up "stoppers" on Amazon and have the following three suggestions:
Ruling out of course, that Racoons are not getting at it at night, and woodpeckers are not getting at it in the daytime, here are three suggestions:
1. If you have a local Wine Kit Store, they have tons of stoppers of different sizes with a hole in the middle for the spout. You could take the feeder in, and ask them if they have a stopper to fit the neck of same;
2. If you have a $dollarrama store, (or equivalent) they sell similar stoppers for in the top of olive oil bottles, balsamic vinegar bottles, etc;
3. Ruling out the possible "creature" factor, and very strong windy conditions, if you are able to find a stopper which tightly seals the feeder neck, and yet the unit still leaks out through the spout, the design is faulty! Don't torture yourself. If you can't return it, give it to someone you don't really like. LOL.
Cheers! Note: I just looked, I have four feeders left over for parts, stupid on my part.
