What you should feed that bird outside your window: 5 science-backed tips

Here’s how science ranks the best seed for common backyard birds!

Preparing for spring means sprucing up the backyard. After you’ve picked out the perfect bird feeder for your space, what the heck do you put in it? The answer depends on where you live and what birds you’re hoping to attract.

5. Sunflower seeds

These are among the most common seeds you’ll find in bird seed mixes, and for good reason. They're beloved by a wide variety of birds, including finches, chickadees, cardinals, jays, and even woodpeckers, reports George Harrison Birds and Blooms. But one major thing to look out for, Harrison says: bully birds.

Species like blackbirds and European starlings are also big fans of sunflower seeds, and that means they're inclined to take over feeders, scarf up all the food, and drive away the pretty, fair songbirds that would otherwise pay a visit.

To get around this problem? Serve up sunflowers in a "exclusion feeder," Harrison says. Some feeders have a small perch (too large for bullies), or a small gate that closes the food source when a larger bird lands on it.

4. Corn (cracked or whole)

Large and small species alike are really into corn: pheasants, turkeys, quails, cardinals, crows, doves, ducks, cranes, and others can all get down with some shelled or cracked corn. (Note: This is not the same corn you buy to pop in your air popper — make sure you're buying seed that's non-toxic to birds.)

However, as the Cornell Lab's website reports, corn will attract more than just birds. You could end up with hungry raccoons, deer, or even bears. It's best to use small amounts of corn, the Cornell website says, and don't use it in tube feeders, since moist corn can grow fungus.

3. Peanuts (!!!)

Famously (though inaccurately) loved by elephants, peanuts are pretty well-loved by a number of bird species. These include jays, crows, chickadees, titmice, woodpeckers, and a whole bunch of others, according to the Cornell Lab. Again, though, you shouldn't be surprised if some other critters — like squirrels and raccoons — show up for a delicious meal.

You can set out peanuts right in the shell, or mix them with other seed. But also similar to corn, peanuts can gather moisture quickly, so it's best to use small amounts and clean out your bird feeder before you replenish it with peanuts.

2. Millet (for four types of birds)

Millet is a common bird seed that you can find in a ton of mixes, and it comes in golden, red, and white varieties. The Cornell Lab says that most birds actually shun millet, which is used as a filler. But commenters on the website Bird Forum have observed that finches actually love the stuff, as do sparrows, buntings, and mourning doves.

1. Thistle (but maybe think about Nyger)

Thistle is a black seed, the shape of skinny long-grain rice. It's a big favorite of some finches — American and lesser goldfinches — and buntings, according to the Cornell Lab. The lab's website notes that since thistle is invasive in North America, people are starting to use a similar seed called nyger instead. It's imported and sterilized by heat to to reduce the chances of the plant spreading across North America.