Picture a diminutive chipmunk trying to stuff a three-nut unshelled goober into his cheek pouch. Jays hide the peanuts in strange places. Next spring, you can go on a treasure hunt, the course charted by the birds. How a bird knows that it should land on plastic netting and, with nearly surgical precision, extract a peanut kernel from the shell, we'll never know. For birds with weaker bills, shelled peanuts are a better choice.
Buyer beware, however.
The bulk seller of bird seed that tries to convince you that the little bitter peanut hearts are the preferred peanut food is either trying to dupe you, or, more likely, just doesn't know what tastes good to most birds. Dr. Al Geis, who headed the U.S. Fish and Wildlife Service's excellent research program on songbird feeding preferences, found that pieces of peanut kernels were the favorite food of white-throated sparrows, bluejays, and tufted titmice. The hearts, however, the peanut product most commonly found for sale in bird feeding specialty stores, were highly attractive only to starlings, a species most people do not welcome at their feeder. Chopped peanut kernels are terrific sources of protein and fat for some birds that infrequently visit feeder, such as thrashers, thrushes, creepers, wrens, and some warblers. Try adding peanuts to your feeding menu.