3: Lonely Hearts Ad. For nocturnal animals, finding a mate in the dark is often very vocal or very smelly; the two senses that carry so much information about an individual really come into their own at night, as wildlife sound recordist Chris Watson discovers when he eavesdrops on the booming calls of kakapo, joins screeching fruit bats in an Australian forest and follows the Scented trail Of moths. Producer Sarah Blunt