Appears to be a lot of Red Fox this year with many people to include myself reporting sightings. Have lots of rabbits (this year and last) which go hand in hand with the litters of course.
I got my start into calling with the Fox. It has become much more cautious about coming in with the larger predator (the Coyote) being around.
My best luck with the Fox is very early morning and using a call with a high pitched clean sounding reed.