Fig. 1
From: Diurnal migration patterns in willow warblers differ between the western and eastern flyways
An example of the FDF identification workflow. a Two cases of three subsequent days for which the middle day shows high light intensity (red line) and low standard deviation (blue line); on one day in autumn (to the left) and one day in spring (to the right). b A scatter plot of daily mean light log intensity against daily mean standard deviation in light intensity. The two filled circles represent the two days from the annual cycle identified as FDFs by inspecting the plots shown in panel a. Colour of circles refers to months according to colour code in panel c. c Boxplot summarizing standard deviation in light intensity per month. Numeric labels near the outliers denote the dates of the corresponding month. In this case, two days (16th Sep and 15th Apr) clearly stand out. The examples are from the bird tagged with logger ID BM199