From: How often should dead-reckoned animal movement paths be corrected for drift?
Animal (number (n) assessed) | Scheduled GPS frequency | DR frequency | Approx. DR length | Extrapolated speeds | Capture and deployment method |
---|---|---|---|---|---|
Lion (n = 10) | 1 Hz | 1 Hz | 2 weeks | DBA-based speed Due to high variability in step gaits, m- and c-values were computed per individual from VeDBA ~ GPS-derived speed regression (cf. [23]) | Prides were lured to bait using audio recordings and individuals were anaesthetised at night according to SANParks operational procedures—detailed in SANParks’ ‘Standard Operating Procedures for the Capture, Transportation and Maintenance in Holding Facilities of Wildlife’ Units were mounted to a Litetrack collar [https://www.lotek.com]. Collars were loose enough to allow three fingers to pass through |
Penguin on land (walking) (n = 15 – 2 DR paths per individual (out- and inbound) | 1 Hz | 10 Hz | 30 min | DBA-based speed Due to having a constant step gait, m- values were selected (c = 0) per individual based on the best scaling relative to GPS path pre-VP correction | Penguins were caught at the nest during the chick rearing season using the clipboard method [74] and cormorants were caught at the nest during the chick rearing season via a crook on the end of a long pole (cf. [75]). Birds were blind folded and restrained on a researcher's knees Devices fitted longitudinally to the base of the spine using Tesa® tape [74, 76, 77] |
Penguin at sea (diving) (n = 15) | 1 Hz | 2 Hz | 1.5 days | Change between constant values (according to behaviour-type) and vertical movement-based speed speed = 0.416 m/s (cf. [78]) when depth ≤ 0.3 m (cf. [79]) speed = 2.1 m/s (cf. [80, 81]) when depth > 0.3 m and absolute values of pitch were < 10o speed = Δd/tan(θ • π/180) (upper cap of speed derived this way = 3 m/s) when depth > 0.3 m and absolute values of pitch were ≥ 10° | |
Cormorant at sea (flying and diving) (n = 15) | 1 Hz | 10 Hz | 8 h | Change between constant values (according to behaviour-type) and vertical movement-based speed speed = 12 m/s when flying (derived from the heave acceleration (cf. [69]) speed = 0.1 m/s when resting at the sea surface (derived from depth sensor and lack of dynamic acceleration) speed = Δd/tan(θ • π/180) (upper cap of speed derived this way = 3 m/s) during the ascents and descents of dives speed = 0.4 m/s during the bottom phase of dives | |
Tropicbird at sea (flying) (n = 7) | 1 fix every minute | 10 Hz | 3 h | GPS-based speed speed = Haversine distance between GPS fixes divided by the time period between values and linearly interpolated (cf. [82]). Speed values overwritten as 0.1 m/s when birds were resting at sea surface | Devices were placed in a zip-lock bag, inside unheated heat shrink wrap and fixed longitudinally to the back feathers [72] using Tesa® tape [76] |