Lesser Whitethroat Song

They might look like a Common Whitethroat but they certainly don't sound like one. This iconic rattle increases in volume and from a distance, which is usually all you hear. Where it gets confusing is why then bird sings it's sub-song which is very similar to that of a Common Whitethroat's sub-song but is usually much shorter.
Gear: Sound Devices Mixpre 6 ii - Telinga Stereo Mk 3