Our northern goldfinches don't like this new-fangled stuff. With sunflower hearts and nyger in adjacent feeders, they cluster on the nyger and ignore the sunflower.

Our biggest increase in variety came when we added a ground feeder table (although we've fastened it to the side of a fence post out of the reach of the cats). In an urban environment, the main requirement is to provide food that your neighbours don't provide! - in our case, fat, nyger and food for the ground feeders.

Although just when I think I've seen the complete birdlist for our garden something new turns up - this year it was our first greater spotted woodpecker, and a chiffchaff/willow warbler on the ground table.