Fig. 3

Examples of GLS data signatures for three winters: a non-denning (D0), b maternity denning (D1), and c short shelter denning (D0). Top: Daily mean (black) and maximum (grey) light intensity (on an arbitrary scale of 0 to 1) as measured by the GLS is shown with ideal day length at the last capture location (yellow, scaled to 0 to 1). Middle: Mean daily in-ear logger temperature (as minimum record every 4 h; black) is plotted together with its daily range (grey) and surface air temperature at Longyearbyen airport, Svalbard (yellow, Fig. 1). Bottom: Daily count of 'wet' recordings (maximum of 18 = count of 3 during all six 4-h periods during a day) the logger registered using a conductivity switch (black). Vertical stippled and dotted red lines denote behaviour classified as den entry, first den opening and den exit