The four seeds that matter
Black-oil sunflower is the universal attractor (cardinals, chickadees, finches, nuthatches). Nyjer (thistle) feeds finches exclusively. White millet feeds the ground crew (juncos, sparrows, doves). Suet feeds the woodpecker clan year-round. Everything else — mixes heavy in milo and filler — mostly feeds squirrels and the ground beneath.
The four-feeder yard
One tube feeder (sunflower) for perching birds, one nyjer tube for finches, one ground or platform tray (millet) for doves and juncos, one suet cage for woodpeckers. Four feeders cover every common visitor; a dozen feeders cover every squirrel strategy — start with four.
The maintenance that keeps birds healthy
Clean feeders monthly (10% bleach solution, rinse, dry), rake under feeders seasonally, and store seed dry. Salmonellosis spreads at dirty feeders — the House Finch conjunctivitis outbreaks taught the hobby this lesson. Feeder hygiene is bird conservation at the kitchen-window scale.