It's not the downwind turn - it's the shear penetration.
Many pterosaur species (the piscivores) also depended heavily on this sequence.
It's a fascinating way of extracting energy from the atmosphere.
Colin Pennycuick did a superb job of describing it in birds many years ago.
As an aside, using a bell lift distribution rather than elliptical can facilitate it, but that was more common in pterosaurs.