This article looking at the role of broadband FM sweeps used by bats that forage in dense clutter came out online in July, but is now in print in the October issue of FE.
Schmieder, D., Kingston, T., Rosli, H., & Siemers, B. (2012). Sensory constraints on prey detection performance in an ensemble of vespertilionid understorey rainforest bats (Kerivoulinae, Murininae). Functional Ecology 26: 1043-1053. DOI:10.1111/j.1365-2435.2012.02024.x
There is a video for the “lay audience” that explains the work here