As Alexander Robertson observed when the picture was exhibited in 1979, the subject of a heron by a lonely mountain tarn is a recurring theme in Grimshaw's work. He attempted it as early as 1865, basing the composition on a photograph, and Robertson suggests that the present version may have been painted about 1868, the date being added later. 'The weird webs of mist draped across the hills do not occur in any other picture, and the particular painting technique, reminiscent of watercolour, is not used after 1870.'