 This means that the bat can get an almost continuous stream of information – essential when objects are close, because they will pass by quickly – without confusing which echo corresponds to which call.A constant frequency (CF) component is often used by bats hunting for prey while flying in open, clutter-free environments, or by bats that wait on perches for their prey to appear.The success of the former strategy is due to two aspects of the CF call, both of which confer excellent prey-detection abilities.