If you wish to attract birds right now, with or without a feeder, brush your mangy old dog of his shedding fur and put the results on the back deck, porch, or wherever. It will soon be gone, put to use in bird nests.
If you want to attract spring warblers, leave a hose dripping water to splash down into an iron kettle or some such. Warblers love the sound, and will fly to it. Few songs are sweeter than that of a passing spring warbler.