I would have to say the squirrel distress works.
I was out squirrel hunting years ago with my
Ruger 22 pistol. I shot a gray squirrel out
of a tree. When the squirrel hit the ground
it immediately started squealing loudly, with
in seconds a gray fox came running out of no
where grapped the squirrel and never missed
a beat. I could only sit there under a tree
with my mouth open in disbelief. That was
an exciting experience.