In January, when temperatures fall below 0 °C and the vipers have settled into their winter shelters, we inspect the artificial burrows that were installed at the release sites. Our aim is to find out whether the vipers are using the burrows that we have provided, and to identify any other animal species that may be hiding within them. We use an industrial endoscope with a flexible camera tube to carry out this task. This allows us to observe the animals in underground burrows without disturbing them.
This year, we examined a total of 65 burrows across 10 sites where meadow vipers had been released in previous years. During the inspections, we recorded eight adult Hungarian meadow vipers and one shed skin. We were able to identify each snake using the high-resolution by the number and arrangement of the scales on their heads.
At one site, the camera captured the first observation of a previously released animal. In one of the habitats within Fertő–Hanság National Park, we found a female meadow viper that had been released in 2020, at the age of three. This means that the eight-year-old snake has successfully survived four seasons in the wild. Since her release, we have encountered her six times, including the most recent inspection. In May 2022, we caught her while she was gravid, and camera traps photographed her three times, providing images suitable for individual identification. In the restored habitat near Fertő, three snakes chose to hibernate together in the same burrow. Although this is not common in meadow vipers, it does happen that several snakes select the same burrow, or sometimes they even share hibernacula with other reptile or amphibian species.
During our inspections, we often find rodents occupying the artificial burrows. Following winter, we remove these nests, to ensure the burrows remain accessible to snakes all year round. One of the burrows even had an unusual and rarely seen resident — a common newt had found shelter there.
