Browsing by Subject "ihmisenhaju"

The populations of several birds have declined in Finland and overall, in the boreal zone during the last centuries. There is not only one reason behind this decline in the populations of the birds, because it is a result of many different factors and combinations of these factors. Especially, the nesting success of birds affects the size of the bird population. Artificial nest experiments are commonly used for measuring the nesting success of ground-nesting birds worldwide. Artificial nests are done with eggs of some bird species, and the meaning of this is to mimic the real nests of the chosen ground-nesting birds. Usually, the aim with artificial nests is to figure out the number of predations and the distribution of predator species in the research area. Nowadays artificial nests are often monitored with trail cameras. The credibility and truthfulness compared to the situation of real nests have awakened a lot of discussion among researchers (ex. Skagen et al. 1999, Weldon 2022). Especially, the human scents and subjectivity in the setting stage is believed to decline the credibility and the comparability of artificial nest experiments. This master's thesis, figured out with artificial nests and signposts, does the human scent work as a source of bias in artificial nest experiments. The subjects of this research were decided to be mammal predators because these animals search for food mostly with olfaction. From a scientific perspective, the experienced mammal predator group included both small and medium-sized predators. In this master's thesis, the directions from where the mammal predators came to the experimental setups in relation to where the research came from were analysed. The data of this study was collected from a large area where there is human impact in Finland, during the spring and early summer of 2021. Three kinds of experimental setups were used: experiment nests, control nests and signposts. All experimental setups were monitored with trail cameras during a seven-day period, during this time researchers do not visit the area. The experiment and control nests were made in natural nesting places. Depending on the habitat the nests would have been nests of waterfowl, ring-necked pheasant (Phasianus cochicus) or capercaillie (Tetrao urogallus). The experiment nests were done in the ground by digging as natural nest holes as possible with wood stick, and after this, four pheasant eggs were placed in the nest holes. Control nests were done same way as experiment nests but without any eggs. The signposts were done by setting commercial predator lure made from the scent gland of grey fox (Urocyon cinereoargenteus) with 20cm wood stick to the underside of small flat stone (rain cannot wash the lure away). After this the stick was placed upright next to the stone to spread the smell. The purpose of signposts was to mimic natural territory signs of predators, and to attract predators to the experimental setups. The signposts were made in the same areas as the experiment and control nests. The data consist of 178 experiment nests, 75 control nests and 79 signposts, so in total the data were collected from 332 experimental setups. The modelling of the data was done with R -program and Microsoft Excel. The situation of the first visits (sector analyses) and the survival of experiment nests was analysed by using Generalized linear model (GLM). The situation of all visits was analysed by using G-test (Goodness of Fit). For the analyses, the directions where the mammals came from, were divided into four sector categories. The directions were imagined as a circle around the setup and the circle was divide into four equal-sized sectors (90 degrees each). The sector that the researcher used was always the number one and trail camera was set up in the middle of the sector. There were four most common mammal predators included in the analyses of the directions: raccoon dog (Nyctereutes procyonoides), red fox (Vulpes vulpes), European pine marten (Martes martes) and European badger (Meles meles). This research showed that despite the common beliefs, scent of a researcher does not lead the mammal predators to the experimental setups. According to the results the cues of human scent did not increase the risk of setups found by predators. Neither the passage of time did not change the relation of used sectors in the situation of the first visits. In the situation of first visits mammal predators preferred side sectors (sector two and four) in the experiment nests and signposts, but in the control nests mammal predator did not prefer any sector. There is obvious need of further research because the reason why mammal predators preferred side sectors stayed unclear. The species-specific analyses showed that raccoon dogs, pine martens and badgers arrived in the experimental setups from random directions. However, as expected red foxes were sceptical and avoided the human used sector and the opposite sector three. This research showed that the predatory behaviour of mammal predators is not completely known and there is still need for further research.