Why are you feeding meal worms to wild birds? If you have a captive or injured bird, they're excellent, but if a wild bird is out there anyway, let them eat the normal worms that come their way.
It adds up, buying meal worms, so you should get a plastic bucket with a tight lid, put a few air holes in, fill the tub with oatmeal and dump your meal worms in. Keep it in a dark, dry, room-temperature place. Every so often take a thin slice of potato and drop it in on top of the oatmeal. Open it periodically and scoop out some worms. Ignore the beetles, they're the ones making new worms.