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  • Benny Miles posted an update 3 years, 1 month ago

    Evaluation of orientation data and statistics Based on the bird’s activity in the cage as recorded by claw marks in the white pigment of the Tipp-Ex and Thermo papers, we visually estimated the mean angle of orientation relative to geographic north using a classification method described by Mouritsen (Mouritsen, 1998) and first developed by Rab?l (Rab?l, 1979). We modified the method by using the limit for a minimum of 40 registrations similar to what we have been using in previous experiments (?kesson, 1994; ?kesson et al., 2001), enabling us to compare the activity levels among tests. The direction associated with ATP7A the highest concentration of scratch marks was visually inspected and marked for each registration paper on a light table. By using a 360�� protractor in the funnel together with the paper, the position of the chosen direction was translated to the closest 5��. The scratch distribution was then evaluated with concentration and activity indices on a 0�C4 scale (Mouritsen, 1998). The activity index was set by estimating the amount of scratches on the whole paper made during one hour, where 0 is 2000 scratches. The concentration index indicates the uncertainty, or scatter, of the direction and was estimated within how many degrees 10 people would point out the bird’s direction (see Table II in Mouritsen (Mouritsen, 1998)). Experiments were included in further statistical tests when both find more indices were �R1, and the sum of them was �R3. Number of experiments classified as active, inactive, disoriented and included in the analyses, are given in Table?1. For individuals with a significant axial mean orientation (56 out of 483 experiments), we used only the side of the axis with the majority of the registrations for further statistical analyses. We used circular statistics to calculate the mean orientation for each species and experimental Wnt inhibitor condition, and the Rayleigh test to analyse if the mean orientation differed from a random distribution (Batschelet, 1981). Differences between groups were compared with Watson’s U2-test (Batschelet, 1981) and Mardia’s test for homogeneity of concentration parameters (Mardia, 1972). We used 95% Confidence Interval (95% CI (Batschelet, 1981)) to analyse if the mean orientation differed from the expected migratory directions along an initial great circle route for birds ringed in Sweden (Fransson et al., 2008) or from the Sun position during the experiments. The Earth’s magnetic field and Sun’s azimuth The geomagnetic parameters, i.e. total field intensity, inclination and declination, were calculated by GEOMAGIX based on the model for the World Magnetic Model (WMM 2005) for the test site at 1 September 2008. The azimuth position of the Sun in the middle of the test hour was calculated relative to geographic north for each date and time of experiments.