Limited success of radio frequency identification technology in locating nests of a crevice-nesting seabird, the ashy storm-petrel

Abstract

Locating the breeding or refuge sites of burrowing or crevice-dwelling animals is a difficult undertaking, particularly for cryptic and secretive species. Here, we summarize our efforts to use Radio Frequency Identification (RFID) technology to locate nesting sites of ashy storm-petrels Hydrobates homochroa on Southeast Farallon Island, Farallon Islands National Wildlife Refuge, California, USA. We deployed a total of 799 RFID tags on storm-petrels captured in mist nets across three breeding seasons from 2017 to 2019. We then attempted to relocate tagged birds in suitable nesting habitat across the island. We employed both passive and active searching strategies over the course of three different breeding seasons and had the most success finding storm-petrel nests using passive searching with stationary RFID readers, although detection rates were low. We found probable nests for an average of 3.1% of tagged individuals with stationary readers and no individuals with an active search method. We suggest that while stationary RFID readers were more successful than active methods, we cannot recommend the method for locating nesting storm-petrels because of the labor involved and low success rate.