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

    RESULTS We found high migratory activity for our experimental birds, i.e. 89.4% of the experiments resulted in registrations of migratory activity (>40 registrations) with mean orientation significantly different from random in the orientation funnels (Table?1). Only 43 (8.9%) of the tests were classified as non-active and in 8 (1.7%) of the tests the birds were disoriented showing no meaningful orientation in the cages. In 84.3% of all tests the sum of both indexes was �R3. Out of a total of 483 experiments 56 (11.6%) of the tests resulted in an axial distribution with r2>r. There was no significant difference in orientation of the dunnocks tested in 2008 and 2009 under natural clear skies (Watsons’s U2 test: U2?=?0.06, p>0.5) and in simulated overcast conditions (Watsons’s U2 test: U2?=?0.04, p>0.5), and therefore the two groups were pooled in further analyses. Table 1. Number of active, inactive and orientation tests classified CP-690550 mw as disoriented for each experimental category and species (dunnock, European ATP7A robin, sedge warbler) in autumn Orientation under natural clear skies All three species showed preferred orientation towards southwest to southeast in experiments performed under natural clear skies and in the local geomagnetic field (Fig.?1A, Fig.?2A, Fig.?3A; Table?2). The mean orientation was significantly different from the position of the Sun in the middle of the test hour for sedge warblers (��: 145��, Sun: 264��; p<0.05, 95% CI ��33��; Fig.?3A; Table?2), dunnocks (��: 153��, Sun: 114��; p<0.05, 95% CI ��37��; Fig.?1A; Table?2), as well as for European robins (��: 250��, Sun: 268��; p<0.05, 95% CI ��13��; Fig.?2A; Table?2). The mean orientation under clear skies for all species was significantly selleck inhibitor different from the expected migratory directions as calculated for ringing recoveries (Fransson et al., 2008) of birds ringed in Sweden and recovered during the autumn migration and wintering areas (mean orientation based on ringing recoveries for sedge warbler: 193.9��; dunnock: 209.0��; European robin: 217.7��; p<0.05 in all cases, 95% CI). For the dunnock and the European robin, the preferred orientation recorded in the cages was directed between the expected migratory direction and the direction towards the sun during experiments (Table?2). Fig. 1. Results from our outdoor orientation cage experiments with juvenile dunnocks, Prunella modularis, at Stensoffa Ecological Field Station in South Sweden during autumn migration. Fig. 2. Results from our outdoor orientation cage experiments with juvenile European robins, Erithacus rubecula at Stensoffa Ecological Field Station in South Sweden during autumn migration. Fig. 3. Results from our outdoor orientation cage experiments with juvenile sedge warblers, Acrocephalus schoenobaenus at Stensoffa Ecological Field Station in South Sweden during autumn migration. Table 2.