PIT tagging does not measurably reduce reproductive success in sensitive burrow-nesting seabirds

Abstract

Abstract Investigator disturbance while monitoring seabirds often results in lower survival rates and breeding success, leaving lasting negative impacts on the population and biased observations. Puffins, in particular, are more sensitive to investigator disturbance than many other seabirds, and researchers must seek to decrease their disturbance and time spent at puffin colonies. Radio-Frequency Identification (RFID) via Passive Integrated Transponder (PIT) tags is an inexpensive and reliable way to identify individuals when coupled with automated RFID detectors, potentially avoiding the need for recapture for nocturnal seabirds. PIT tags either can be implanted subcutaneously or attached externally to leg bands, but it is unclear which method causes lower disturbance. To examine the impact of PIT tagging on rhinoceros auklets (Cerorhinca monocerata; a member of the puffin clade) nesting in artificial burrows on Middleton Island, Alaska, during the 2022 breeding season, we monitored burrow entrances with automated recording RFID readers to collect presence and nest attendance data. PIT tagged and control birds had similar breeding success and chick growth rates. Birds tagged externally were detected less often than birds marked with a subcutaneous implant. We conclude that PIT tagging on the rhinoceros auklet is a relatively non-invasive method for seabird monitoring, and that subcutaneous implants doesn't cause more disturbance than external attachment.