Complex sentence: During a stoop the raptor folds its wings and makes its body shape as streamlined as possible, although the stoop is still under control by altering the tail and extending a wing-tip when and where necessary.
Split into simpler sentences: During a stoop the raptor folds its wings and makes its body shape as streamlined as possible. Although the stoop is still under control by altering the tail and extending a wing-tip when and where necessary.