Monitoring GPS-collared moose by ground versus drone approaches: efficiency and disturbance effects

Efficient wildlife management requires precise monitoring methods, e.g., to estimate population density, reproductive success, and survival. Here, we compared the efficiency of the drone (equipped with an RGB camera) and ground approaches to detect and observe GPS-collared female moose (Alces alces) and their calves. Moreover, we quantified how drone (n = 42) and ground (n = 41) approaches affected moose behavior and space use (n = 24 individuals). The average time used for drone approaches was 17 minutes compared to 97 minutes for ground approaches, with drone detection probability being higher (95% of adult female moose and 88% of moose calves) compared to ground approaches (78% of adult females and 82% of calves). Drone detection success increased at lower drone altitudes (50-70 m). Adult female moose left the site in 35% of drone approaches (with > 40% of those moose becoming disturbed once the drone hovered < 50 m above ground) compared to 56% of ground approaches. We failed ..., There are two data sets, one containing moose GPS data at a 10-minute fix rate three hours before and after drone or ground approaches had started, and one at a 2-hourly fix rate one day before and after drone or ground approaches had started.
For drone approaches, the drone (“DJI Mavic 2 Enterprise Dual” using a GPS+ GLONASS system with a ± 1.5 m horizontal and ± 0.5 m vertical accuracy range) was programmed to fly to the last known GPS position of the moose (flight speed was 6 m/s) at 100 m altitude while the operator stayed ≥ 500 m away (but within the visual line of sight). When the drone arrived at the last known position, the operator manually searched for the moose and – if it was detected – flew the drone over the exact location of the moose, where it hovered for two minutes while recording video, using a built-in RGB camera (1920x1080 resolution). If the moose did not flee from the site, the drone was progressively lowered to 70, 50, 30, and 20 m altitude with a 1-min hovering ..., , # Monitoring GPS-collared moose by ground versus drone approaches: efficiency and disturbance effects

[https://doi.org/10.5061/dryad.cnp5hqccv](https://doi.org/10.5061/dryad.cnp5hqccv)

## Description of the data and file structure

Both data sets (10-min and 2-hourly GPS locations of moose) contain information concerning the individual moose ID, date and time, latitude, longitude, period (before or after an approach had started), the type of approach (treatment), moose step length, the presence of a calf/calves, the distance to the closest road, whether a moose was flushed or not, and tree cover density.

### Variables and their descriptions

* IndividId = ID of the GPS-collared moose
* Rounded_hour = Date and rounded local time when the GPS position was taken
* Latitude = Latitude of GPS position
* Longitude = Longitude of GPS position
* Period = Period of approach; i.e. before or after the approach had started
* Treatment = Type of approach (drone, ground, or control)
* ...