Originally Posted by
john_tullamarine
A bit similar to tacking in sailing vessels
Similar, but with an important distinction: in either case you need an inertial frame of reference that is decoupled from the moving air. A sailboat achieves this by sticking a big fin (keel or centerboard) into the water; conceivably an albatross achieves this via physical inertia while transiting the transition between layers of air that are moving in different directions relative to each other.
Ultimately their aint no free lunch, though. unless you continue to see a sharp gradient between wind velocity vectors across a very short distance, you're out of harvestable energy. I'll bet (being way to lazy to figure this out) that the albatross is fully at one with the "new" wind by the time it is 50 meters or so into it, and has run out of inertia imparted by the "old" wind by then.
All this aside, let's pause for a moment to contemplate how spectacularly beautiful the albatross is, eh?