Wouldn’t it be great with a single culturing powder with a multiple mix formulation that could produce few kinds of Drosophila? That is exactly what I am doing. As more varieties of fly available in your farm, it will attract more birds. I am culturing about 5 mixed formulations with different kind of fruit base. In about 5-7 days they should show some results. This means that in a single jar you would have few different types of fly (D.Melonogaster, D.Funebis, etc)
It’s just like we are going to a buffet fest and the restaurant only serves one dish and the next door restaurant serves 5-10 dishes, so which one would you go to? I guess most of you knew the answer already.
Swiftlets like to fest, most of the time you will see them in colonies charging at group of different insects especially after rain. So if your farm has varieties of Drosophila it will attract more birds than those that have only one type of flies or none.