Alligators are predators, so there always looking for food. the second they hear the call they look right at the area the sound is coming from..so make sure your out of sight.
I have seen alligators go under the water as i was calling and popped up right in from of me. so be on the look out when calling.
Remember Alligators have great sense of smell, sight and hearing, so when you set up to call be very quite, out of sight and down wind.