A Comparison of Census and Monitoring Techniques for Leach’s Storm Petrel

Abstract

Abstract Leach’s Storm Petrel (Oceanodroma leucorhoa) is a difficult species to census because the birds nest in burrows, are nocturnal, and spend most of their life at sea, only coming ashore to breed. Simply locating a suspected petrel burrow is inadequate for management and conservation purposes because it is not known if the burrow is in use. The traditional method, of “grubbing”, or reaching into suspected burrows to determine occupancy, is invasive, and of limited accuracy. Playback of specific calls during the nesting period may be used to check for burrow occupancy. I conducted a test of grubbing in comparison with vocal playbacks and use of a portable video camera to determine which methodology was most accurate, least invasive and most efficient in time and cost investment. The use of playbacks showed the most promise as a quick, low cost method for surveying these burrowing petrels. The camera method, though as thorough as the playbacks, was more expensive and time consuming, while the traditio...