Hulled sunflower seed (which means "without hulls") is often sold as sunflower chips, sunflower hearts, or no-mess sunflower seeds. It is very convenient, and attracts a wide variety of species to your feeder, but it is pricy compared with black-oil sunflower seeds in the shell.

Or is it?

Sunflower hearts.

An apples-to-apples comparison of the price of a T-bone steak to a fillet requires you to discount the weight of the bone and consider only the cost of the meat. Black-oil sunflower seed is 35 to 45 percent hull—inedible to birds. That means when you buy a 50-pound bag of it, you're buying roughly 30-pounds of bird food and 20 pounds of waste. Consider that next time you're shopping for birdseed. A fair comparison would be a 50-pound bag of standard sunflower seeds to a 30 pound bag of sunflower hearts. Odds are, hulled sunflower seeds will still be more expensive than standard, in-the-shell seeds. But you won't have a mess to clean up under your feeders. What's that worth to you?

Indigo bunting at a safflower feeder.

Also consider that safflower seed, while typically much more expensive than sunflower, has a smaller hull, so less of its weight is waste. Squirrels and starlings aren't fond of safflower seed, so if mammalian marauders or birds you don't like are eating you out of house, home, and black-oil sunflower seeds, consider a switch to safflower. A gradual switch, mixing the two seeds, is recommended.