I have installed a bird feeder in the tree at the end of the garden. It accepts Nyjer seed, and attracts finches. The feeding hole is tiny, as is the seed itself and it seems that only finches can feed from it.
The visitors are mainly goldfinches, and these colourful red black and gold birds are delightful.
I had thought that nyger was a type of thistle, but apparently not. Nyger information: