the most popular call would be rabbit distress,the rabbit distress calls in more predators then any other call.but rodent,bird,kitten,puppy any distress sound will work.i'll have to agree with howler on the repetitiveness of elec calls for coyotes,they just don't seem to responed well to elec calls.they work on fox but for coyotes get good with some hand calls.this dosn't mean that elec callers don't work becouse they do,its just that hand calls will concistantly produce more responces.i do use a group howl tape for locating several hours before first light but i don't use it to work them in.i carry both types with me but most times will use the hand calls on stand.my favorite call might not be yours,you need to experiment and find calls your comfortable with and have succsess with.succsess builds confidence,confidence means succsess.a good howler is a very important part of hunting coyote,you may not use it at every stand but you need to have one with you for when it is needed and you need to know how to use it.open reed,closed reed,variable pitch calls all have there pros and cons but you should have at least one open reed call with you.being from PA you find out that closed reeds calls like to freeze up,although opens reeds are harder to use they won't freeze up.its realy a matter of personal preference when it comes to calls.