Sammendrag
In this report, we summarize the field activity and some results emerging from the first three years of field studies of rock ptarmigans in the municipality Lierne in Nord-Trøndelag county, Norway. During this period, we have applied a range of different field methods, including radio telemetry (based on VHF collars), point-count surveys and capture-recapture studies based on DNA extracted from ptarmigan scats. Radio collaring was conducted in the area around Lierne National Park, and during the winters 2012 and 2013 we collared 84 rock ptarmigans. In total, nine was reported as shot by hunters during the winter (n=6) and fall (n=3) hunting seasons, and 33 other mortalities were recorded (from predation and unknown causes). A large proportion of the ptarmigans left the study area between February and the start of the breeding season. We estimated that, given that the bird was alive, it was about 20% probability that it was still in the study area at the onset of the breeding season. Our study design did not allow us to estimate immigration in to the study area, and the results does thus not necessarily reflect the difference between the size of the winter and the summer populations. It does however indicate a large turnover of individuals between seasons. Further, the longest movement from the capture site that we documented was 79 km, and 15 ptarmigans were found at least one time >30 km from the capture site. Further, in April 2013, we conducted a pilot study aiming at establishing a field protocol for point-count surveys of rock ptarmigan in the spring. In total, 70 points were visited, of which 25 were visited twice. Based on these data, we estimated a mean detection probability at p=0.39 (95% C.I. 0.22–0.61), whereas the occupancy was (ψ) was estimated at 0.79 (95% C.I. 0.49–0.99). Based on these experiences, a similar pilot project conducted in Finnmark in 2015, and published methods from Svalbard, we have developed a first version of a field protocol for point-count surveys for rock ptarmigans that can be used as a basis for more large-scale surveys. During 2014 and 2015, we also sampled ptarmigan scats for DNA based capture-re-capture studies across a 25 km2 study area at Lifjellet. So far, we have collected data across three seasons (spring 2014, winter 2015 and spring 2015), with multiple visits in each season. We apply a robust design, making it possible to estimate abundance or density within seasons, and survival between seasons. Based on preliminary analysis, we consider this a very promising approach for future studies on rock ptarmigan population ecology.Lierne kommune, Nord-Trøndelag, Fjellrype, Årsrapport, Viltforskning
Lierne municipality, Nord-Trøndelag county, Rock ptarmigan, Annual report, Wildlife research
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