Two connoisseur's birds

Both warblers and both of the Acrocephalus family - distinguished by their sloping forehead, long beak and habit of living in reed beds amongst other things.
The one on the right is a common bird in the UK although most people will not known they have see - or more likely heard - one. The one on the right is similar to another common British bird, the Reed Warbler. This one however has been on steroids and is seriously larger and so is, not surprisingly, called a Great Reed Warbler. A real bruiser of the warbler world.