The term WAGTAIL is a 4-letter word that can be solved by the crossword clue 'LARK'. A wagtail is a type of bird in the family Motacillidae, which includes pipits and longclaws. They are known for their long tails, which they often wag from side to side. Wagtails are found in many parts of the world, including Europe, Asia, Africa, and North America. They are usually found near water, and feed on insects, worms, and other small invertebrates.