If you're among the 59 million Americans the U.S. Fish and Wildlife Service says feed wildlife around their homes and you're searching for a bird seed that squirrels won't eat, there's a pretty good chance you're wasting your time.

"There really isn't a seed they won't eat," said Emma Greig, project leader at the Cornell Lab of Ornithology's Project FeederWatch. That includes safflower seed and seed mixed with cayenne pepper, the two allegedly squirrel-proof seeds that bird-feeding enthusiasts most frequently suggest.

"We don't recommend cayenne because, though it's probably harmless for birds, there haven't been any really careful studies about it," said Greig. "We tend to err towards recommending that people not add stuff to bird seed. Also, squirrels can sometimes get used to the cayenne pepper or other spicy add-ons, so it doesn't even work for all squirrels. It's hard to have a rule that applies to every backyard, so it might work in some cases. But, it's also possible to get it on your fingers if you are adding it to seed and then get it in your eyes. That's something to be mindful of if people do want to use cayenne pepper."

If you're not familiar with Project FeederWatch, it's a winter-long survey of birds that visit feeders at backyards, nature centers, community areas and other locales in North America. The site offers a wealth of information for those at all skill levels in all seasons.

Instead of looking — probably in vain — for a food that squirrels won't eat, Greig suggests trying to out-wit them. As impossible as it sounds, there are several things you can do that will give you a fighting chance at exactly that, she says.

Squirrels enjoy corn, too

One is to enact an "if you can't beat ‘em, join ‘em" strategy. In other words, offer them an alternative. "Some people have said squirrels actually prefer cracked corn," said Greig. She suggests scattering cracked corn on the ground as a way of drawing the squirrels away from feeders. She also suggests hanging ears of cracked or dried cord from nearby branches.

Seed and feed stores and the bird seed sections of box stores, garden centers and stores that specialize in bird products are likely sources for this type of corn. Will corn on the cob you can buy at the local grocery work? Greig isn't sure. She suggests trying a less expensive way first. But, she concedes, you never know until you try it!

Not all feeders are the same

A second way to outwit squirrels that Greig knows will work is to use weight-sensitive squirrel-proof feeders from Brome Bird Care called SquirrelBuster feeders. "When a little bird perches on them to get food, the seeds remains accessible," says Greig. "But if something as heavy as a squirrel lands on the feeder, a metal plate goes down and covers the opening to the seed, so there is no way for the squirrel to get to the food and get their little food reward."

Do the squirrels just get frustrated with this type of feeder and eventually give up? "That sort of behavior is different for every individual," said Greig. "Some individuals might be really persistent, inquisitive and bold. Some individuals might give up quickly. There's no really hard-and-fast rule about what will happen with the squirrels in your own backyard. It's about trying different things and seeing what works."

That's what the Cornell Lab did in its bird garden. They found that their only truly squirrel-proof feeder is a tube feeder that's mounted on a pole more than 10 feet from any type of cover that can serve as a jumping-off point. This setup has a 16-inch baffle fastened about a foot below the feeder bottom. The baffle also serves as a feeding tray that catches seed spilled from above. If you don't have an open area, the lab suggest trying a tilting baffle placed above the feeder. Usually, the lab points out, when a squirrel lands on such a baffle it will simply slide off. For feeder placement purposes, be aware that squirrels can leap 8 feet horizontally or jump 11 feet down from a roof or tree branch onto a feeder.

Why bother with a baffle at all? Why not just grease the pole and sit back and watch them climb up and slide back down? The lab doesn't recommend that because the grease could have chemicals toxic to wildlife and the grease can mat feathers or fur, which could cause both squirrels and birds to freeze to death in winter.

Squirrels just won't give up

squirrel reaching across to bird feeder Squirrels will return to feeders because of their instinct to remember where food is available. (Photo: blewulis/Shutterstock)

What makes them so persistent? After all, the greater lengths people go to deter squirrels, the harder squirrels seem to work to beat the system.

"I think it's just the way these little creatures have evolved," said Greig. "They cache food, so they have to remember where they cached the food, and they have to extract food from all sorts of nut and food sources. That's how they have managed to survive in the forest. So, these behaviors get applied to our bird feeders. They are just little problem solvers. Once they figure out a problem with one feeder, it probably makes them a little bit more likely to try to solve a problem on another one."

For additional problem solving tips to keep squirrels off bird feeders, including seeing what others have done, Greig recommends checking out Tips From FeederWatchers about deterring squirrels, such as the slinky squirrel baffle, in the FeederWatch Community section. There are lots of tips here for other bird-feeding solutions, so just scroll through the section looking for squirrel tips and tricks.

Another spot on the site she recommends is the FAQ portion of the Learn section.

You might also want to follow the blog on the site. It contains a lot of information about feeding birds in general, but you might be especially interested in this post about a squirrel-proof feeder set-up.

If you've found a solution that works in your own backyard, post it — and photos or videos — in the comments section below.

If you're still searching for a solution, just know that you're not alone. "I think that these are just curious animals by their nature, and that has helped them be able to find food in the wild," said Greig. "It's what I think they have evolved to be."

For more information about squirrels and bird feeders, the lab suggests reading "Outwitting Squirrels," by Bill Adler Jr.