Cardinals like safflower seed.
Feeding the flock
It takes more than good luck to attract a variety of birds you want to see and ensure there will be little waste under the feeders. Here's some advice on matching the right food in a proper container so the birds will flock in and feed on a cold day.
Most of the bug-eating birds flew farther south when it started getting cold. The insects skedaddled, laid their eggs and either died or crawled under the bark and into the duff to survive. A few of the hardier "meat-eating" birds stuck around. Creepers and woodpeckers that probe crevices and bark looking for larvae will warm up quickly to a suet feeder full of fat-rich blends. Jays and chickadees like suet too.
You can make your own mix of raw beef suet, shelled raw peanuts, dried corn and some bird seeds slowly rendered or melted and poured into a bread loaf pan to harden. Slice the suet into slabs just under an inch thick and slip them into a square suet feeder with coated wires to keep the squirrels at bay. When selecting fat for suet-making, try pure kidney beef fat or rendered fat from deer meat, both of which are highly digestible. Avoid any fat from smoked or cured meats like ham. Birds are put off by smoky, salty mixes and won't touch them.
If you'd rather not cook, make it easy on yourself and just buy premade suet cakes at pet supply or feed stores. Most of these cakes cost about a buck and are preformed to fit in suet feeders. Also, the commercial suet mixes are composed of fats that don't drip if the weather warms up a bit. You can leave them up all year if you like.
It only makes sense that most of the birds you see in winter are seed eaters. The favorite all-around seed is black oil sunflower – thin-shelled, high in calories and adored by a wide range of birds from cardinals and nuthatches to sparrows and other flocking birds. Platform feeders or V-shaped covered feeders that have a bottom trough are fine dispensers for these seeds. Hang the feeder from a tree branch or on a pole equipped with a squirrel guard. These black oil seeds are much more palatable to birds than larger grey striped sunflower seeds and there will be far less waste under your feeder. On the other hand, doves and juncoes would rather feed on the ground and appreciate a little scattered seed.
Tube feeders are fine for holding white millet and smaller seeds that attract a mix of birds, especially sparrows and juncoes. Use tube feeders that provide small access holes and perches but are too small for squirrels to find a hold.
Small fine-wired tube feeders or feeders with fine slits can handle niger (also called nyger and thistle seed) that is irresistible to finches and chickadees alike. The seed is a bit more expensive, but very little of the seed gets wasted as birds extract each seed from the feeder.
Safflower is a bigger off-white seed that tastes somewhat bitter. Cardinals like it and squirrels are definitely not fans of safflower, so it is an excellent choice if the bushytails regularly get into your feeders. It works well in both platform feeders and trough style bird feeders.
Avoid the big cheap bags of bird seed that seem like too good a value to be true. These seed mixtures often contain high percentages of less palatable seeds like red millet that many birds won't eat. A large percentage of such seed may just end up scattered on the ground under your feeder attracting rodents. Some birding organizations, like nature centers and local Audubon Society chapters, work with seed providers to blend high quality bird seed mixes that they sell seasonally as a fundraiser. Check that out in your area.
Another important draw in winter is fresh water. If you can provide a bird bath with a small heater to keep water thawed out and you place the source of water near your feeders, you will draw in far more birds.
Cleaning feeders and bird baths every few weeks in winter also slows disease spread where birds congregate. Change seed regularly if it gets wet or if birds defecate on the seed. Discard moldy seed in the garbage or bury it in a compost pile. When cleaning feeders and baths, wear rubber gloves, and scrape off any loose seed or feces outdoors with a wire brush, putty knife or paint scraper. Then take the feeders inside to a utility sink. Do not clean bird feeders and waterers in a kitchen sink and risk contamination of your dish washing and food preparation areas. Scrub feeders with hot water and a soapy solution. Rinse the feeders and bird baths thoroughly, and then rinse them again with clean water to which you have added a little household bleach. Rinse out this solution and air dry feeders and bird baths before refilling.