Wilkingson, Gerald S. and Janette Wenrick Boughman.  "Social Calls Coordinate
Foraging in Greater Spear-Nosed Bats."  Animal Behavior.  Vol. 55.  1988.
Pp. 337-350.
Although most studies on screech calls from bats have focused on mating and
courtship patterns, there is a strong case to be made that bats eavesdrop in
order to find some feeding spots.  Gerald S. Wilkinson and Janette Wenrick
Boughman write, "Calls that attract mates should be produced during the mating
season by the sex with higher variance in mating success.  Alarm calls, on the
other hand, should occur in the presence of predators, particularly when
vulnerable individuals, such as the young are at risk.  Food calls might
either repel or recruit other animals""(337).    These "food calls" can also
advertise food availability.  In which case, other bats can find the food.  If
this happens, food availability may become scarce or foraging may become
difficult and highly competitive.

In a study conducted by Wilkinson and Boughman, bats were captured over a
period consisting of five, nonconsecutive months. During this period, the
calls of the female bat were recorded, played back and coded.  What was
discovered proved to be interesting.  Female bats from the same foraging
groups produced more calls than male or female bats from different foraging
groups (341).  In essence, they communicated the position of food.  However,
there is no data to reveal that they are creatures who rely upon eavesdropping
to find food.