Density Can Be Misleading for Low-Density Species: Benefits of Passive Acoustic Monitoring Rogers, Tracey L. ; Ciaglia, Michaela B. ; Klinck, Holger ; Southwell, Colin Abstract Publication: PLoS ONE Pub Date: January 2013 DOI: 10.1371/journal.pone.0052542 Bibcode: 2013PLoSO...852542R