Ladybirder, I put out a niger feeder about 2/3 months ago and nothing, yet the seed was very slowly going down. Then about a forthnight ago, I happened to look out of the window at about 6am, two gold finches troffing away, I've kept an eye out and they are back at the same time each morning. Two days ago they were there at about 7pm, and I've spotted them several times since at the same time and only the pair of them.
So dont dispair they may be visiting, its just finding the right time to see them. I'm sure mine must be nesting close by as they are always together.