hatch some brine shrimp ?
check any standing water
lakes, slow moving streams troughs and water tanks that are in disuse
before you do that tho set up some containers and add a handfull of grass, manure, yeast or some other such food and let it sit ( depends on size to how much) then you can add some of what you collectto each of these so you have a supply
Of course if you do run out of food for axy babies they will just eat each other so its not that big a deal eh
HTH