Many birds eat insects, and adding mealworms to your feeders is easier than you think and will provide a nutritious snack that will be especially appreciated by summer birds with hungry nestlings to feed.
Mealworms are the larvae of the mealworm beetle, Tenebrio molitor, also called the darkling beetle or tenebrio beetle. The larvae themselves may also be called yellow mealworms or golden grubs, and they're pure gold for the birds that eat them. With a size from 1-1.5 inches long, these insects are a rich source of protein that is necessary for muscle development in birds. At the same time, however, they are low in calcium and should not be the exclusive food offered at backyard feeders.
Mealworm beetles do not fly and the insects do not pose a threat to humans, though there have been some report of breathing problems similar to asthma when discarded molts and other debris from raising mealworms is allowed to accumulate.
Birds That Eat Mealworms
Any insectivorous bird is likely to enjoy a treat of mealworms, and most passerines are at least partially insectivorous when they are feeding their chicks – the protein of insects is essential for proper chick nutrition. Birds that are likely to sample mealworms from backyard feeders include:
- Eastern and western bluebirds
- Indigo buntings
- Gray-headed catbirds
- Black-capped and Carolina chickadees
- Rose-breasted and black-headed grosbeaks
- Northern mockingbirds
- White-breasted and red-breasted nuthatches
- Baltimore orioles
- American and European robins
- Summer and scarlet tanagers
- Tufted titmice
- Blue and great tits
- Yellow-rumped and prothonotary warblers
- House, Carolina and winter wrens
While not all of these birds will eat mealworms exclusively, they are likely to at least sample the insects, especially if other food sources are scarce and they have hungry chicks demanding food. Any other birds you have regularly visiting your feeders may also try a mealworm snack if the insects are available.
In addition to birds, other animals may eat mealworms, including mice, rats, cockroaches, frogs and snakes. Mealworms can even be consumed by humans and are often found in health food stores or as part of tequila candy.
How to Feed Mealworms
Mealworms can be fed to birds as live insects or in dried or roasted forms. The live insects are much preferred, and the movement will help attract hungry birds, but birds at feeders will eventually discover dried mealworms as well.
Live mealworms should be offered in a shallow dish with straight, smooth sides, such as a plastic or glass container or a specialized mealworm feeder with a solid bottom and high enough sides to contain the insects. They can climb out of rough containers, and even sides of smooth containers should be at least 1-2 inches deep so they cannot escape. Dried or roasted mealworms can be offered in separate containers or mixed in with seed, suet or fruit for more balanced nutrition.
Because mealworms are not complete nutrition for birds, it is best to offer them in limited quantities only. Filling a small dish once per day can provide sufficient mealworms to give birds a treat or to offer parent birds a helping hand with finding enough insects to feed their young, without leaving leftover insects that can attract pests or rodents.
Mealworms can easily be purchased at local wild bird stores, bait shops, pet stores or through online retailers, but many backyard birders who may feed hundreds of mealworms per week opt to raise their own at a much cheaper cost. Raising mealworms is not difficult and can be a fun science or homeschooling project for children, a 4-H or scouting project or a family activity.
To raise mealworms, start with adult worms or beetles and provide them a home in a shallow container (a plastic shoebox with ventilation holes in the top is ideal). The bedding and food mixed at the bottom should be 2-3 inches deep, and could include a variety of nutrition sources for the growing larvae, such as corn, oat or bran meal or other grains. A source of moisture such as a few apple or potato slices or a wedge of cabbage or lettuce will help maintain the right humidity for the insects as well as provide additional food.
The insects should be kept at room temperature up to 75-80 degrees for ideal growing conditions. It can take 2-3 months before the first harvest of edible mealworms is grown enough to feed the birds, but each week the bedding should be freshened and changed to minimize mortality and keep the insects healthy. Once harvested, the fresh mealworms can be fed to birds immediately or could be stored in the refrigerator (they will enter a semi-dormant state) until needed, but be sure allow at least a few worms to mature into beetles to propogate the next generation of mealworms.
Mealworms can be a great treat to feed birds, and even squeamish birders can learn to love these insects that provide essential nutrition for their backyard birds, whether they opt to purchase mealworms or raise their own.
Photo – Mealworms © Howard Dickins