The beautiful harlequin frog, a species facing extinction, was photographed in Colombia by student contestant Khristian Valencia (Credit: Khristian Valencia/BES)

It is often said that "a picture is worth a thousand words." That is certainly true of the mesmerizing images of fleeting moments of nature submitted by international ecologists and students for the British Ecological Society's (BES) annual photography competition. Here are a few of 2019's winning entries, announced on November 28, 2019.