The wren, its Latin tag is 'Troglodytes troglodytes', because they had been observed near caves. (Troglodyte being a cave dweller, from the Greek trogle 'hole, mouse-hole' and dyein 'go in, dive in' - apparently).
Wrens are famously good singers, and can hit two notes at the same time, delivering a powerful song, which becomes an angry chatter when an intruder, human or otherwise, passes through their territory.
The female becomes particularly vocal if her newly fledged brood is on site, which may explain why wrens tend to be thought of as female, hence Jenny Wren.
Some cultures, however, prefer a masculine character to support the regal notion and, in Germany, the bird is known as Zaun-könig or hedge king.
The loud song from such a small throat is possible because birds have an organ called a syrinx with a resonating chamber and membranes that utilise virtually all the air in the lungs and can produce two notes at the same time.
