The Grasshopper Warbler is one of many warblers in the UK. It is one of the less common ones, although Northumberland seems be be blessed with good numbers. To look at they are not all that distinctive, but they are extremely easy to identify (and locate) by their song, which is a prolonged reeling trill, which can last for quite a while. The song has been nicely described as being like the clicking made by a freewheeling bicycle.
