Light-level geolocator analyses: A user's guide

Simeon Lisovski*, Silke Bauer, Martins Briedis, Sarah C. Davidson, Kiran L. Dhanjal-Adams, Michael T. Hallworth, Julia Karagicheva, Christoph M. Meier, Benjamin Merkel, Janne Ouwehand, Lykke Pedersen, Eldar Rakhimberdiev, Amélie Roberto-Charron, Nathaniel E. Seavy, Michael D. Sumner, Caz M. Taylor, Simon J. Wotherspoon, Eli S. Bridge

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

22 Citations (Scopus)

Abstract

Light-level geolocator tags use ambient light recordings to estimate the whereabouts of an individual over the time it carried the device. Over the past decade, these tags have emerged as an important tool and have been used extensively for tracking animal migrations, most commonly small birds. Analysing geolocator data can be daunting to new and experienced scientists alike. Over the past decades, several methods with fundamental differences in the analytical approach have been developed to cope with the various caveats and the often complicated data. Here, we explain the concepts behind the analyses of geolocator data and provide a practical guide for the common steps encompassing most analyses – annotation of twilights, calibration, estimating and refining locations, and extraction of movement patterns – describing good practices and common pitfalls for each step. We discuss criteria for deciding whether or not geolocators can answer proposed research questions, provide guidance in choosing an appropriate analysis method and introduce key features of the newest open-source analysis tools. We provide advice for how to interpret and report results, highlighting parameters that should be reported in publications and included in data archiving. Finally, we introduce a comprehensive supplementary online manual that applies the concepts to several datasets, demonstrates the use of open-source analysis tools with step-by-step instructions and code and details our recommendations for interpreting, reporting and archiving.

Original languageEnglish
Pages (from-to)221-236
Number of pages16
JournalJournal of Animal Ecology
Volume89
Issue number1
Early online date13-Jun-2019
DOIs
Publication statusPublished - Jan-2020

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