Figures and data
Foxtrot migration and dynamic winter range scheme.
a) Foxtrot migration. The color bar along the y-axis corresponds to the color coding of the habitats in panel b of the chart on the right. b) Dynamic winter range.
Foxtrot migration of Rough-legged buzzards.
Q – quick phase. Qf – Quick fall phase (orange), Qs – Quick spring phase (yellow), S1 – Slow phase, 1st part (light blue), S2 – Slow phase, 2nd part (dark blue). a) Change in the latitude of 43 Rough-legged buzzards during the year, red line – mean latitude of all birds, black vertical lines – mean dates of start and end of the migration phases, blue vertical line – mean date of the minimum latitude. Grey, sky blue, and piggy pink shaded areas – standard deviation of the means. b) Migration map. c) Difference in the migration parameters between the migration phases. Lines on the direction plot (down, right) represent the mean value for each bird; arrows represent the mean direction.
Parameters of the rough-legged buzzards’ migration.
Vegetation land cover during quick and slow phases.
a) Quick phase (spring and fall periods together). b) Slow phase (1st and 2nd parts together). c) Migration map.
Snow cover conditions during the slow phase of the foxtrot migration.
a) 95% Minimum convex polygons (MCPs) of Rough-legged buzzards during winter. Arrows indicate the direction of the movement across months. OCT – October, NOV – November, DEC – December, JAN – January, FEB – February, MAR – March, APR – April. b) Snow cover conditions for the real situation (black) and two hypothetical situations – if birds spend the winter in the place where they arrived after the fall migration (green) and if birds fly directly to the southwest and stay there all winter (red). Dots represent mean values, error lines – standard errors.
The use of foxtrot migration research for the assessment of the non-breeding range and conservation status of a particular species.
a) Christmas counts, often used to determine winter range, may give a misleading representation of non-breeding range for species with foxtrot migration. b) Changing the conservation status of a species based on reduced abundance in a particular area may not be appropriate for species with foxtrot migrations. Red – breeding range, blue – winter range. Latin numbers indicate the month the birds are present in the area.
