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.