Evaluation of field and analytical methods for estimating the population size of burrow-nesting seabirds from playback surveys

Capsule Acoustic playback methods have been widely used to survey burrow-nesting petrels but playback stimuli typically yield low response rates. Digitally manipulated recordings of the calls of the European Storm Petrel were created with the aim of producing an acoustic "super-stimulus" which could be used to elicit a higher response rate to improve population census methods. However, the manipulated recordings elicited a lower response than those that were unmanipulated. We also compared two methods for estimating population size of European Storm Petrels based on playback responses and found that the du Feu method is more widely applicable and precise than the standard method widely used in the UK and Ireland.