Are Mealworms safe?
The Internet has recent sported people stating that feeding mealworms may be a problem for wild birds. It is not!
The following article talks about the relationship of calcium and phosphorus whereby phosphorus will bind with calcium and can cause a deficiency of calcium absorption in birds.
The article points out that the real issue is with captive birds; not wild birds. Wild birds will balance their diet and most feeding stations offer a variety of food besides mealworms.
Calcium, Phosphorus and Vitamin D3 Imbalances by Peter Sakas DVM, MS.