Birds Crave Mealworms

Almost all back yard birds eat insects, and mealworms are high on their list of favorite snacks. Here's everything you need to know about attracting flocks of birds with mealworms.
European Robin eating a mealworm

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Almost all back yard birds eat insects, and mealworms are high on their list of favorite snacks. Here’s everything you need to know about attracting flocks of birds with mealworms.

Mmm Mmm Mealworms!

Oh, you thought they were just for bluebirds? Nope. Chickadees, titmice, sparrows, woodpeckers, robins, wrens, orioles, tanagers, warblers, blue jays, starlings – you name it. Pretty much any bird that eats insects will eat mealworms—in bulk! (Chickens too, in case you’re thinking of getting into the backyard chicken movement.)

Put out a few mealworms for your birds and they’ll be gobbled up before you can say “The early bird gets the …”

Exactly What Is a Mealworm?

A darkling beetle. Photo credit: Hatem Moushir, CC by SA 4.0

Mealworms, which are also known as ‘yellow mealworms’ or ‘golden grubs’ are not actually worms. What they really are is the larval stage of the Tenebrio molitor darkling beetle, one of a huge family of black beetles. This one is a grain eating insect that lives on stored grain. The larvae are an inch to inch-and-a-half long and are quite harmless.

Why Feed Mealworms to Birds?

Mealworms are high in both calories and proteins, which make them great supplements to give your birds in both winter when insects are hard to find and in spring, when nestlings need to grow strong muscles before leaving the nest.

They contain enough vitamins and minerals to rival beef and are available for birds in live and dried forms.

Note: Humans also snack on mealworms and you may see them in the grocery store. Don’t feed these human-food worms to birds – they may have unsuitable additives. (In case you’re wondering, mealworms are said to taste like nutty shrimp.)

How to Offer Mealworms

Bluebird eating live meal worms. Credit: C. Watts, CC by SA 2.0

Dried mealworms can be mixed in with other bird food or served alone in any kind of feeder (I use an old cookie pan.)

Live mealworms can climb any rough surface, so pop them into a glass or smooth plastic dish about two inches (5 cm) high. You can also get a variety of mealworm feeders especially for this purpose. These can be useful if you want to limit the mealworms to specific birds, like bluebirds or chickadees instead of feeding every greedy starling for miles around. (Guess what happened to my mealworms???)

Dried vs Live Mealworms

Is it better to feed live mealworms or dried ones? That probably depends on the season. Mealworms have hard outer shells made of chitin that makes up most of the insect when dried. The crunchy shells are hard for young birds to digest and may be less appetizing to any birds in the warmer months when there’s plenty of juicier bugs to be had. But in winter when birds need high calorie foods to stay warm and insects are hard to find, a freeze-dried mealworm looks a lot more appetizing.

Dried mealworms. Look closely and you’ll see that some are just empty husks. Photo by theilr, CC by SA 2.0 via Flickr.

Some bird lovers spray the dried worms with a light coating of olive oil or soak them in very hot water for an hour or longer before putting them out. They say the birds seem to like them better that way.

See how much juicier live mealworms are? If you were a bird, you’d love ’em! Photo by Magnus Hagdorn, CC by SA 2.0

If you want to offer dried mealworms, you can get them online from Amazon and many other suppliers. (Live mealworms are also available online if you want to try those.)

Dried mealworms can be stored the same as bird seed; live mealworms should be stored in a cool but not freezing spot (in the fridge maybe?) to keep them from developing into beetles.

If you are going to be keeping live mealworms in your fridge for more than a couple of weeks, take them out for a few hours so they can eat and get fresh air. Be sure discard any that are discolored or dead and don’t feed those ones to your birds as they could cause food poisoning.

Squeamish about live worms? Fear not. Live or dried, mealworms are not wet or slimy, don’t bite and aren’t poisonous. You can handle them with your bare hands or (as I did) with a scoop or wearing gloves.

What Are ‘Giant Mealworms’ and Should You Feed Them to Birds?

So-called giant mealworms, often sold as reptile food, are just regular mealworms with one important difference: commercial growers treat them with s-methoprene, a biochemical pesticide that acts like a juvenile growth hormone, preventing pupation and causing mealworms to grow larger. It’s available to licensed users under several different brand names.

S-methoprene is considered ‘slightly toxic’ (or ‘relatively non-toxic’, depending on which side of the industry you’re on) to birds. According to a paper given at the West Nile Virus Action Workshop 2000, birds may show symptoms such as slowness, reluctance to move, sitting, withdrawal, and in-coordination as quickly as two hours after consuming just 0.5mg/gram of s-methoprene.

These symptoms can last up to two days and would obviously make it much more difficult for affected birds to survive predator attacks.

Giant mealworms as bird food? NOT.

Waxworms and Super worms

Waxworm caterpillar. Photo by skeeze, public domain.

Waxworms are actually the ivory-colored caterpillar form of the Greater Wax Moth Galleria mellonella. Unlike mealworms, they have a soft outer body, which makes them easier for baby birds to digest, and contain lots of moisture too. Waxworms are a great food to offer in springtime.

Waxworms are available online too, and can be stored in a cool place (50-55° F or 10-12° C) without feeding for three or four weeks.

Note: Waxworms are also treated with a biopesticide that stops them from maturing. I’ve been unable to pin down the exact chemical, but it seems likely to be Azadirachtin, which is a component of Neem oil. Neem oil is considered non-toxic to birds.

Superworm Zophobas morio

Superworms (sometimes called Kingworms, Morio worms or Zophobas) are the larvae of another type of darkling beetle, Zophobas morio. They look something like mealworms but are much bigger (up to 2.5 inches or 6 cm) and have a softer exoskeleton. They have six stubby legs and strong mandibles. (Yes, they do bite so don’t let your pets investigate them!)

Superworms won’t mature into beetles if they are kept in a container with lots of other superworms and plenty of food.

This is another type of live feeder worm you can buy online.

A Worm to the Wise: Don’t Overfeed

Mealworms, waxworms and superworms are nutritious and tasty—birds of all kinds will devour them by the bucketful if you let them, but you shouldn’t. Unfortunately they’re high in phosphorous, which means that digesting them results in a net calcium loss to the bird, leaving less calcium for healthy bones and egg shells.

If you’re feeding just one breeding pair and their chicks, 100 or so worms twice a day is plenty.

So, are you going to add worms to your feeding schedule? Which ones will you use? Let me know in the comments below.

Top Image: European robin eating a mealworm by Fsphil, CC by SA 3.0via Wikimedia Commons

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5 Comments
  1. Great article for”birders.” I’ve known about “mealworms” for some time but was not aware of so many other kinds of worms.

    • Thanks Pat, much appreciated! I didn’t know until I wrote this that one could have live worms shipped directly to your house. I always thought you’d have to go to a bait shop.

  2. Well wonders never cease, I never knew what a mealworm was, not to mention the different kinds of worms. Love the photo’s too.

  3. My daughter abd I were ‘guilted’ into taking a tiny parrow home one day when she was pretty done by her riding teacher. The woman told her if she didnt want to try and raise the little bird, she only rescued swallows, she’d just give the tiny thing to one if the barn cats. I walked up just in time to hear the last part of the story and see the tears running down my daughters face. We foubd another riding stable and began our new hobby, bird rescue. lol (once you take one every one hears of your soft heart)
    We learned alot, made as few mistakes as we could but the one that tore mebup was when I didnt do my homework on mealworms n chitin well enough. I knew it could cause blockages but not how few it took.
    We ended up with a few imprinted invasive species birds, a House Sparrow and several Starlings. The Sparrow was super intelligent and all the Starlings talking clowns! The leader of the comedy crew was a male Starling named Kiwi. He’d sit with the boys as they played video games rooting em on or with my daughter as she read telling her sge was pretty then saying ‘Kiwis oretty too!’ ‘Kiwi needs wormies now’. We were all his slave. We knew to limit his ‘wormie’ addiction. But one week on z couple night 2 kids double dosed him. We knew 6 was enough to give him a day. But to a kid 6 meant 10 or 12. If he was eating other food and drinking alot of water that was a stretch but not too bad. But several times in 2 days he got ‘double dosed’. We figured he got 20 in one evening and 18 the next afternoon. He had eaten fresh food and had water but the build up of chitin was too much. We could not find a vet that Saturday night or Sunday who would see our beautiful bird we’d hand fed from a hatchling. All I got was ‘He’s just a Starling’. He just cried n cried n called our names for 2 days as we took turns keeping him warm n trying to give him sips of fluids. We took him in Monday for a Necropsy. He’d died Sunday night because he’d ate too many stupid mealworms. The Chitin had blocked his gut. If it can kill a bird thats a primary insectivore I have to warn people they are really a poor choice for seed eaters feeding their young on an insect based nestling diet. Youd be far better to supply them with wax worms or give the parents seed or fruit to power them so they can hunt better insects for their young! Mealworms are not that nutricious! Black fly larvae have 75x the protein! Look it up n you will see! Feed stores sell much better choices for chickens and other poultry you can use! Dont do the damage to a bird that I did.

    • Hi Silver,
      Thanks for sharing your experiences. It sounds like the birdies were a lot of fun for the kids. However, it’s probably better to take orphaned and injured birds to a wildlife rehab center than to care for them yourself. The rehabbers will know what’s best for the birds, and you will avoid exposing yourself and kids to the many diseases (60+) that wild birds commonly carry.
      Cheers,
      Joy

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