| Summary: | Maintenance and Update Frequency: asNeeded Statement: MK-19 GLS tags (Biotrack Ltd., Wareham, UK) are well suited for tracking small Procellariiform seabirds due to their miniature size (16×14×6mm, 2.5g) and inexpensive cost. Prior to the pre-laying exodus a threshold weight of 540gwas used when choosing individuals for tag deployment, to ensure that no birds in poor condition were included in the sample. Due to an improvement in post-migration body condition following the pre-laying exodus the minimum weight for tag deployment was increased to greater than 580 g. Biotrack MK-19 GLS tags sample light level every minute and record the maximum light measurement in every five minute period, which is the primary data for estimating initial location. They also sample the time when an activity (wet or dry) state change occurs, with water temperature recorded after twenty minutes in the wet phase, which acted as auxiliary environmental data for estimating initial location. Prior to deployment, GLS temperature sensors were calibrated, in a water bath at 2 °C increments between 0 °C to 24 °C and then at 28 °C, to cover the SST range of the expected foraging area. Individual tags were placed in an open space for three days at the deployment location to produce a sequence of light recordings at a known location from which solar elevation estimates could be calculated. After retrieval, the raw archived tag data was downloaded, and adjustments for internal clock drift were made. The 2010 tracking work is part of a multi-species study funded by the Australian Animal Tracking And Monitoring System (AATAMS) Facility of the Integrated Marine Observation System (IMOS). In 2012, slightly different GLS tags (MK3005 V608, Biotrack), was deployed. These are recognised by the company manufacturing as comparable to the MK-19 tags. Track estimation was performed in R with the package SGAT (which is freely available on GitHub). The locations for each bird represent the mean locations of each twilight from the 12,000 possible fitted ...
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