I've used home made callers for years, keep your ice Lilly sticks, thicker ones are best !
Get some old audio music tapes and a roll of black tape.
Around the end of each stick wrap a couple of turns of tape to create a small gap. Then place the tape on the end of a stick and using the black tape wrap it a couple of turns.
You then stretch it nice and tight over the end and back to the start,wrap it off again keeping the tension tight.
Cut excess and marry up to the other stick, tape both together.
These are really effective and with a bit practice can pull them in from a good distance.