About Suet, Mealworms, and Other Bird Foods

April 20, 2009
Yellow-bellied Sapsucker by Don Rash/Cornell Lab Yellow-bellied Sapsucker by Don Rash/Cornell Lab.

Seeds are a great way to get birds into your yard—but they’re not the only food group out there. Birds have varied diets and some of the following foods will help you attract an even greater selection of birds.


Not Recommended:

red-headed woodpecker at suet feederRed-headed Woodpecker at a suet feeder. Photo by Mike Smith/Cornell Lab.


Suet is technically defined as the hard fat around the kidneys and loins in beef and mutton, but in common usage, most kinds of beef fat are also called suet and can safely be fed to birds. Suet is particularly attractive to woodpeckers, nuthatches, chickadees, jays, and starlings. Wrens, creepers, kinglets, and even cardinals and some warblers occasionally visit suet feeders. Animal fat is easily digested and metabolized by many birds; it’s a high-energy food, especially valuable in cold weather.

Raw suet grows rancid quickly when temperatures are above freezing; don’t offer that except in winter. When suet is melted and the impurities removed (“rendering”), it keeps much better, but can still get soft during warm weather. When suet gets soft, it can coat belly feathers, a dangerous situation especially in spring and summer when birds are incubating—tiny pores on the birds’ eggs may get clogged, preventing the developing embryo from getting enough oxygen.

Suet cakes are blocks made from suet or a thick substitute mixed with other ingredients, such as corn meal, peanuts, fruits, or even dried insects. Because corn and peanuts can provide a growth medium for dangerous bacteria, it’s important for you to make your own suet cakes or to buy them from reputable dealers. It may be prudent to keep suet cakes made with corn, cornmeal, or peanuts refrigerated until using.

Starlings are very fond of suet. To dissuade them, offer suet in a feeder that requires birds to feed hanging upside down. Woodpeckers, chickadees, and nuthatches will access it easily, but starlings cannot.

Peanut Butter

In winter, especially in cold climates, peanut butter is a nutritious food to offer birds. Peanut butter sold in grocery stores is certified safe for human consumption, and is safe to offer birds when cold or cool temperatures keep it fairly hard. In warmer weather it must not be kept outside long enough to become rancid or soft.

There is some concern that soft peanut butter can stick to birds’ mouths. To make it grittier, cornmeal can be added, but because both corn and peanuts provide excellent media for bacterial and fungal growth, make sure peanut butter feeders are cleaned out frequently. Peanut oils can separate in both pure peanut butter and in mixtures. If these oils adhere to a nesting bird’s feathers, they can be transferred to eggs, plugging the pores, so never provide peanut butter mixtures that become soft or oily.


Mealworms are larvae of a flightless insect called the darkling beetle. They’re a serious pest in granaries, but are safe and easy to maintain in our houses, confined in buckets or plastic bins.

Mealworms can be an excellent source of protein, calcium, and vitamins for a great many birds, including some that normally don’t visit feeders, but mealworms are only as healthful as the diet they are fed. If you order them in bulk, they usually come packaged in wads of newspaper, and will eat the paper, ink and all. So make sure to remove them from the paper as quickly as possible when they arrive. It can be tricky to remove them from their packaging—it’s easiest to avoid setting them free in your house if you transfer them from the packaging to your buckets outdoors, or over a very large piece of white paper so you can spot any runaway mealworms before they get far. They don’t live long away from an easy supply of food, but few people relish the thought of them, dead or alive, in crevices in their homes.

To maintain a large number of mealworms, fill the bottom of an ice cream bucket, dishpan, or similar bin with an inch or two of dry oatmeal or wheat bran. Add chunks of raw potato or apple for moisture, and then put the mealworms in. To improve the levels of many nutrients, especially during the nesting season, you can add powdered hand-feeding bird food (the kind marketed as a complete diet for hand-reared baby parrots).

Mealworms can’t escape a plastic enclosure such as a bucket as long as there are at least two or three inches of vertical wall between the surface of the medium and the lip. Keep them in the coolest place in your house—usually a basement is a great choice—on a surface where the bucket won’t easily get knocked over.

There’s a lot of excellent information about mealworms on the North American Bluebird Society website and about how to raise them on the Sialis website.

So very many birds will voraciously gobble up mealworms at feeders that offering them is only affordable if you set out a few at a time, at feeders inaccessible to birds you don’t want to subsidize. Small acrylic window feeders work well; if yours has drainage holes, make sure to plug them because mealworms can squeeze through surprisingly tiny spaces. Special bluebird feeders that exclude most other birds are available commercially, or plans are available here.

northern cardinal and pyrrhuloxia side by sideNorthern Cardinal (left) and Pyrrhuloxia (right) visit an apple in an Arizona backyard. Photo by Joan Gellatly via Birdshare.

Fruits and fruit seeds

In the tropics, many people set out fruit for birds, attracting a large number of tanagers and other species that people in North America seldom consider “feeder birds.” But even in the north, robins, thrushes, waxwings, bluebirds, mockingbirds, catbirds, and tanagers can sometimes be attracted to feeders providing fruit. Because few people in the United States or Canada offer fruit at feeders, few individuals of these species have experience eating at feeders, so it can be tricky to entice them to get close enough to figure out the concept. Fresh berries; chunks of fresh apples, melons, or grapes; or frozen berries, are excellent choices. Raisins or currants that have been softened by soaking in water may also be good. Orange halves are particularly attractive during spring migration, especially to orioles.

Providing fruits can cause some serious problems. It spoils quickly, so feeders must be emptied and cleaned very frequently. Offering fruit in a plastic cereal bowl makes this an easier task. Unfortunately, in summer, fruit attracts ants and wasps; fortunately, there’s no compelling reason to feed fruit in summer and fall when so much fresh fruit is available naturally.

Pumpkin seeds and other squash or melon seeds can be extremely attractive for birds. Bake them or spread them out to dry completely, and then run them through a food processor to chop them up, which will make them easier for smaller birds to eat.


Orioles, catbirds, and sometimes Cape May Warblers can be enticed to visit feeders offering jelly. Make sure to only offer very small quantities at once, because jelly gets extremely sticky; small birds can become mired in it. Also, jelly has much higher sugar concentrations than any natural food. It’s probably not unhealthful for adult birds to supplement their diets during severe food shortages associated with unseasonable cold spells in spring, or in small quantities during the rest of the year. Sometimes adult orioles and other birds visit jelly for a quick snack while searching out insect food for their young in summer; this won’t hurt them.

white-breasted nuthatchWhite-breasted Nuthatch by Ronaldok via Birdshare.

Grit and minerals

Eggshells are an excellent source of grit and calcium, but chicken eggs may harbor the salmonella bacteria. Shells from hard-boiled eggs were sterilized in the cooking process, but if you provide eggshells that weren’t cooked, bake them for 20 minutes at 250 degrees Fahrenheit, let them cool, and then crush them into pieces smaller than a dime. Offer eggshells on the ground, in a dish, or on a low platform feeder, separate from your seed feeders.

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Not recommended. Putting out leftovers may seem like a way to avoid waste, but it’s not usually a good idea for feeding birds in your backyard. It’s possible for the food to spoil and be unhealthy for songbirds; and it’s quite likely to attract European Starlings, House Sparrows, or even more undesirable species such as rats, mice, and raccoons.

Bacon drippings

Not recommended. Bacon drippings are animal fat just like suet, and many birds will eat it. But bacon virtually always has detectable amounts of nitrosamines, carcinogenic compounds formed from some of the preservatives used in bacon. In particular, the very high cooking temperatures used to fry bacon are conducive to nitrosamine formation. So despite the fact that birds love it, bacon and bacon fat pose too much of a risk to the long-term health of birds to warrant using it.