Browsing by Author "Kylmä, Tapani"

When concerning birdlife, Helsinki has two major wetland areas; the shores of Vanhankaupunginlahti and Östersundom. These areas include both natural wildlife conservation areas, and Natura 2000 -protected areas. In addition to an abundant nesting waterbird population, sightings of rarer birds and other vertebrates also occur regularly. The number of pairs of birds and their population density are on top of Finland’s rates. The eutrophic sea gulfs with their plentiful array of vertebrate species lure in small carnivorous mammals. In the valuable birdlife areas, the main concern is the predation pressure imposed by these mammals onto nesting birds. The fox (Vulpes vulpes), badger (Meles meles), pine marten (Martes martes) and the invasive alien species, raccoon dog (Nyctereutes procyonoides), all prey on birds and their eggs. To ensure the vitality of the bird population and other species, it is justified to hunt for the small preying mammals on the wetlands in question. On the lands of the city of Helsinki, Helsinki City Construction Services’ unit of nature preservation is primarily responsible for the hunting. The traditional hunting method uses traps that catch the targets alive. Since these traps have to be checked in person once a day, this method is extremely time and resource consuming with a large number of traps. Utilising modern trail cameras with remote control option and realtime photo transmission is a way to save the time used for hunting considerably. The first objective of this study was to find out just how much time could be saved in the trap hunting of preying mammals when using trail cameras that send realtime photos and could be remotely controlled. To achieve this objective, I collected data of how long trap visits and moving between them took. Furthermore, I obtained information about the frequency of different occurrences around the traps. Using this data, I compared workdays with varying number of traps and the aforementioned two hunting methods. The study shows that as the number of traps increases, the time save does so also when using trail cameras. The biggest difference is in the time used moving between traps, since the trail cameras eliminate unnecessary visits. This enables resources to be used towards keeping more traps active, which increases the efficiency of the hunt and thus may benefit the wellfare of waterbirds and other animals. The second objective was to utilise the photographic material of small carnivorous mammals and to determine their trap catching rate, and study the possible differences between different predator species. Clear divergences were found between these probabilities: the raccoon dog and the badger had the highest catching rate (55 % ja 57 %, respectively), while a pine marten would be trapped with 38 % probability, and a fox with only 12 %. The divergences were tested with an χ2–test, and exluding the raccoon dog-badger pairing were statistically significant.