A fine time for resolving animal movements; the case for dead-reckoning

GUNNER, RICHARD; QUINTANA, FLAVIO; YODA, KEN; YAMAMOTO, TAKASHI; BROGGER, MARTÍN; GABELLI, FABIÁN; WILSON, RORY P.

Congreso; THE 7TH INTERNATIONAL BIO-LOGGING SCIENCE SYMPOSIUM; 2021

INTERNATIONAL BIO-LOGGING Society

Understanding what animals do in time and space is important for a range of ecological questions, including resource selection and networks of space-use. Animal-attached devices conventionally use VHF transmitters or GPS devices to verify an animal?s location. The quality of interpolations between these ?Verified Positions? (VPs) depending on the temporal- and spatial resolution of the system. This affects a huge variety of factors of ecological interest such as estimates of distance travelled, route-taken and space-associated behaviours. ?Dead-reckoning? ? the construction of animal paths using travel vectors from motion-sensing systems is one method of ?filling out? the missing space-time-use information and can provide critical information between VPs. Here, we review the utility of VP-corrected dead-reckoning using an animal that travels both in water and on land; Magellanic penguins (Spheniscus magellanicus). We demonstrate how measurement error can arise using this method and how to maximise accuracy, including ensuring appropriate behavioural identification, speed allocation, VP error screening and correction rate. We also show how dead-reckoning can highlight specific behaviours, orientation strategies and use of space within ?energy landscapes?. Our results indicate that penguins do modulate their at-sea movements according to current flow and their ability to navigate efficiently between nest and sea phases varies according to habitat type and the amount of horizontal displacement upon return from the sea.