3.4 Quantity and quality of data collected
Among all studies analysed, 107 studies used radio transmitters, 42 used
GPS and 14 studies tracked resources using radio transmitters and/or GPS
tags (i.e. attached to seeds/fruits rather than individuals). One study
used both radio and GPS tags to follow animals (Campos‐Arceiz et al.
2012; Asian tapirs). The mean number of tags deployed per species per
study was 17.48 ± 1.67, the median 10, and n = 206. A total of115
out of 148 animal tracking studies reported information necessary to
calculate deployment successes. Of these, 49 studies (33.1%) recorded
tag failure (tag loss, battery failure, insufficient data for analysis
etc), whereas 66 studies reported a 100% tag success rate. The average
tag success rate across all studies was 86.2%. The tag success rate may
be lower than reported as the remaining 33 studies did not clearly state
whether the figures reported were the number of tags deployed or the
number successfully returned and used in analysis.
Generalised linear models indicated that tracking method was the only
significant predictor of the duration of tags and the number of
locations recorded per study (Fig 4). Studies using radio tags recorded
fewer days (estimate ± std. error = -1.79 ± 0.49, p < 0.001;
Fig. 4a), and locations (estimate ± std. error = -2.01 ± 0.48, p
< 0.001; Fig. 4b), than GPS tags. Neither taxa nor an
interaction effect between taxa and tracking method influenced duration
of deployment or locations collected.