The wren is a paradox of a bird. On the one hand wrens are ubiquitous. They are Britain's most common bird, with 8.5 million breeding pairs and, have by far the loudest song in proportion to their size. They also thrive up and down Britain and Ireland: from the smallest city garden to remote offshore islands, blustery moors to chilly mountains. Yet many people, particularly a younger generation, are not sure if they have ever seen a wren...