Drones help monitor polar bears on Wrangel Island
Polar bears are usually counted in March-April, when females with their cubs leave their birth dens and take their children to sea ice, where they teach them survival and seal hunting skills. The traditional methodology is the following: specialists are divided into groups and several times a week (depending on constantly changing weather) go on snowmobiles around the areas with the highest concentration of dens. At the same time, they inspect each slope, valley and other places where a layer of snow allows the predator to dig out temporary housing. Finding a den is not an easy task. Firstly, most often dens are located high, and secondly, the bright spring sun, reflected on the snow as in a mirror, greatly complicates the process of finding the entrance, which is only a little more than a meter in diameter.
A drone with a thermal camera helps to overcome these difficulties: the temperature inside the den is much higher than outside, and when flying around the territory, a thermal halo can be seen on the drone control panel, and the expert can record and examine the find in detail with a high-resolution camera.
The technique was successful. The work was carried out by eight people in two groups on different areas. On the second day, the drones soared into the sky. Four launches over the first found den (total flight time 1 hour 40 minutes) showed that it was inhabited. Specialists were able to examine in detail not only the female bear, but also its two cubs. The animals reacted quite calmly, although the drone pilots did not violate the comfort zone and observed social distancing.
Despite the freezing temperatures of -25 C and the north wind, the experiment to examine the den was a success. But the main task - to detect the den using a drone - has not been solved.