Mealworms are not really worms at all but are the
larval form of the darkling beetle (Tenebrio molitor). They are clean, easy to
raise, do not carry human diseases and most importantly are a nutritious food
supplement readily accepted by bluebirds.
Mealworms can be offered to bluebirds to:
- Entice them to use a nest box
- Assist the incubating female to find food quickly so she does not have to
leave her eggs for long periods of time
- Act as supplementary food for nestlings if food becomes scarce when
weather conditions prevent the parents from finding insects
- Help them survive during spells of severe winter weather
Care of Mealworms:
Mealworms are easy to raise, requiring only a grain source such as wheat
bran, cornmeal, chicken mash or oatmeal. Add a piece of potato, apple or banana
peel on a piece of paper towel or cardboard about once a week to provide
moisture. Avoid letting the meal itself become too moist. Mealworms can be kept
in a shallow plastic container with a capacity of 2 to 5 gallons, that is
covered with a lid that provides good air circulation (a cover of screen or
perforated metal can be used). Keep the container in the dark, because as the
name darkling beetle implies, they prefer darkness. If you plan on raising
mealworms, a piece of cloth can be placed over a portion of the grain to provide
a surface on which the adult beetles can lay their eggs. The mealworms will
burrow below the surface of the grain and undergo a series of molts. Their
development is most rapid at the optimum temperature of 80° F. After the last
molt, the larvae come to the surface and metamorphose into naked white pupae for
6 - 18 days and then into beetles. Adult beetles have wings but rarely fly. They
lay their eggs 9 - 20 days after emergence and then die. Egg incubation is 4-19
days. Eventually, waste products or "frass" will build up and a slight odor of
ammonia will be detected. At this time, the grain needs to be sifted to separate
the worms and adult beetles from the old grain; the container washed and new
grain added. Dry cat food can be added to the grain to enhance the protein value
of the mealworms for the bluebirds. Mealworm metabolism can be slowed down by
keeping them in the refrigerator for a few weeks, up to several months (remove
the vegetable matter first).
Feeding Mealworms to Bluebirds:
Perhaps the biggest challenge is to try to attract bluebirds to your yard
with mealworms. If you already have bluebirds and just want to ensure they stay,
mealworms can be an effective enticement. If you have never or rarely seen a
bluebird in your yard, chances are they will not show up just because you have
put out mealworms. What will happen is that other birds in your yard will find
them and quickly consume the entire offering. So unless you have bluebirds
around, it could be a costly and unrewarding venture to offer mealworms in the
hopes of attracting them. However, in cold climates, small over-wintering
songbirds like chickadees, nuthatches, etc. appreciate a small hanging tin cup
of mealworms as much as bird watchers enjoy watching them come.
There are several types of feeders that can be used, or you can just scatter
mealworms on the ground. The latter method is least advised as mealworms are
attractive to most birds and they might all be eaten before bluebirds can find
them. The best type of feeder is the hopper style where the mealworms can be
placed inside the feeder with the bluebirds entering from a hole at either end.
Naturally curious, bluebirds will readily explore this type of feeder and
quickly recognize it as a food source. The 1 ½" hole at each end will
effectively exclude larger birds. Smaller birds will soon catch on, but an
aggressive male bluebird will usually defend "his" feeder, especially if he and
his mate are nesting nearby. Some find that putting a flat saucer with a few
worms in it on top of the hopper feeder will help draw the bluebird's attention
to the location of the feeder. Once they become familiar with the routine, the
saucer should be removed and mealworms placed inside the feeder. The location of
the feeder can also be moved as the birds become familiar with it, and then
moved to a spot where it is easier for you to watch them feed. One of the
highlights of feeding mealworms to bluebirds is watching the fledged young start
coming down to the feeder, first begging to be fed and eventually figuring out
for themselves how to get the tasty treats on their own.
Because they should be used as a supplemental food, mealworms should only be
offered once or twice a day unless poor weather conditions dictate more frequent
feeding. A hundred or so worms offered morning and evening would be adequate for
a pair with a box of nestlings.
This information has been provided to you by
the North American Bluebird Society. Be a part of the conservation solution.
Join NABS, The North American Bluebird Society! Contact the NABS headquarters:
The North American Bluebird
Society Dept. B P.O. Box 74 Darlington WI 53530-0074
Please include a self-addressed stamped
envelope for more information.
Copyright © 1999 North American Bluebird
Society
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