The death more than two decades ago, in 1998, of the bear Raven by an anthrax infection triggered by stress that caused the capture to install a radio transmitter in Somiedo (Asturias) caused great trauma at a time when the population of the species was much smaller. The event paralyzed this type of program, which began and ended in Raven. No attempt was made with any native individual in the wild until September last year, when an adult bear was caught in León, in Alto Sil, as part of the plan that intends to install devices at between 20 and 30 plantigrades in the Cantabrian Mountains. . At the moment, everything is going well, they say. The female wandered from September to October between various towns looking for food, waiting to be able to eat the wild fruits of the forest: acorns, beechnuts, chestnuts…, at which point she was no longer attracted to the more urban areas.
The signal disappeared in mid-November, when it was secluded in the osera, an early date to hibernate, which “makes us think that it could go out with a calf, we’ll see”, explains Vincenzo Penteriani, a researcher at the CSIC- Joint Institute of Research in Biodiversity that directs the project. In Spain the only radio-tagged specimens are bears brought from other countries to repopulate or some wounded native animal that has been released once recovered. The species lives in two communities: that of the Cantabrian Mountains with 324 specimens, and that of the Pyrenees, with 64, the latter coming from the reintroduction of Slovenian plantigrades.
“It’s impressive, we have a reference point every half hour, 48 locations a day that allow you to see the entire route, how it crosses the mountains, which towns it goes to,” describes the scientist. In his opinion, there is no better system to know the real data of the adventures of these plantigrades than to install a GPS. “The basis is to mark them, because how are you going to protect a species if you don’t know how and when they move and where they go?” Penteriani assures that Spain is lagging behind other countries with abundant specimens of the species such as Scandinavia or Slovenia. “This project should have been started decades ago and much greater knowledge would have been obtained, especially now that the species is expanding,” he explains. He hopes that the information collected will also make it possible to determine whether highways or roads constitute barriers that prevent bears from reaching new territories, their main causes of mortality, and improve coexistence with man.
During the three months in which they followed the bear until it disappeared in its den, the researchers have verified that it has frequented the towns from dusk to dawn, when the streets are almost deserted, and then returned to the forest and bed. Between two and four in the morning he moved between a gas station and an industrial estate, for example, and at seven in the morning he was already in the forest, his refuge. He approached the urban centers to eat from the fruit trees, in many cases abandoned. “They do it at night, when the streets are more deserted, and during the day they return to the protection of the trees, in such a way that practically no one notices their nightlife,” he says. Many of the inhabitants of these small villages would prefer that the bears stay in the forest all day, without having to share their fruit trees or hives with them.
Penteriani points out that “a lot of noise is made about the conflict that occurs with the bears, but in reality what is perceived is a very natural behavior and, in addition, there is a temporary separation [día y noche] that allows coexistence with these animals that live in a very humanized environment”, he explains. What is impossible to avoid is that some more daring specimen appears, that searches in the garbage or attacks hives, “but for this there are dissuasive methods such as equipping buckets and hives with anti-bear protection methods.”
The legacy of the male who died in the Somiedo mountains in 1998 due to a generalized anthrax infection triggered by a stressful situation (his capture), has meant that on this occasion the measures to prevent damage to them are multiplied. CSIC scientists tested the method in Cabárceno, a park where animals live in captivity in large spaces. “If the specimen is stressed when you shoot the sedative, it can cause a fatal reaction,” says Penteriani. The practices have allowed them to capture the bear in the wild by luring it with food to a culvert-type trap (a kind of trailer where it is locked up). “When the trap is activated, it takes us less than 20 minutes to reach the site, to minimize the risk of harm to the maximum,” he says. They place the trap in places frequented by the specimen: “It is not about leaving them out there and waiting to see if it falls, because that can cause you to be far away and that the bear has to wait inside longer than necessary,” he says. Once captured, he is administered anesthesia, monitored, and undergoes a physical examination and full blood count.
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They have tried another less invasive method that consists of a remote firing system, at a greater distance and without a trap in between, so that “there is no one next door and there is no stress”. But, for the moment, they have not put it into practice in nature. The scientists are working in the Alto Sil with a project of the Junta de Castilla y León with the Government of Cantabria, which the Xunta de Galicia has joined. Asturias has developed a different plan to geolocate bears that approach urban centers and will only install the device in the event that “the rest of the actions to drive them away” do not take effect. The locator emits a signal with the location and warns when it enters a delimited area. In this way, the agents of the Natural Environment will be able to apply dissuasive methods “more efficiently” and disaccustom the bears.
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