No detectable effect of geolocator deployment on the short‐ or long‐term apparent survival of a tropical seabird

A wide range of biologging devices are now commonly deployed to study the movement ecology of birds, but deployment of these devices is not without its potential risks and negative impacts on the welfare, behaviour and fitness of tagged individuals. However, empirical evidence for the effects of tags is equivocal. Global location sensing (GLS) loggers are small, light level recording devices that are well suited to studying the large-scale migratory movements of many birds. However, few published studies have examined their impact on adult survival, a key demographic rate for long-lived species, such as seabirds. To address this, we collate a long-term mark-recapture data set in conjunction with a 10-year GLS tagging programme and examine the impact of tarsus-mounted GLS loggers on the adult apparent survival probabilities of a medium-sized tropical gadfly petrel. We found no evidence to indicate that deployment of GLS loggers affected apparent adult survival probabilities either in the short-term, i.e., during deployment, or in the long-term, i.e., from carrying a device at some point in the past. Annual adult apparent survival was estimated at 0.965 (CIs 0.962, 0.968) during 1993-2018. Our findings suggest that using GLS loggers to document the movements of medium-sized gadfly petrels over multiple years is a viable technique without negatively impacting adult survival. This result has potential relevance to movement ecology studies of other ecologically and morphologically similar seabirds through GLS logger deployments.

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