This time we look at the arrival patterns of warblers. (Please note that each sighting is shown as a vertical black line.)

From the above illustration we can see that all the above four warbler species start arriving  in early September. However, Blyth’s Reed-warbler appears to stay around the longest (until May). Booted Warbler leaves about a fortnight earlier than Blyth’s (mid-April), while Lesser Whitethroat and Hume’s Leaf-warbler stay only until the second half of March. These interesting patterns have only been revealed thanks to observations logged in by keen MigrantWatchers.