Spring: An in-depth look at the wildlife and natural elements that are abundant during the springtime in Scotland. A female mountain hare tests the virility of male contenders by letting them chase her over themountains. Spring is also the season when emperor moths emerge from their silk cocoons. The males immediately start trying to find a mate, picking up the females' scent. Back in Shetland, spring plankton blooms have drawn in humpback whales, overlooked by millions ofseabirds, including 25,000 puffins.