White stork (Ciconia ciconia)

These two tell an interesting story. First of all, White storks undertake impressive annual migrations. They fly several thousand kilometres from their breeding grounds in Europe to their wintering grounds in Africa. Each adult stork has their own favourite wintering location, and juveniles travelling with them will learn this specific migration route, allowing them to travel solo the next year.

Also notice the difference in plumage between these birds: it’s all down to a recent moult or not. With time the brilliant white feathers become smudged and yellowish, the jet black of the wings is lightened into a dark brown by the sun, and the white edges of the primaries and secondaries wear off. White storks take a long time to moult though; most adults fully replace their flight feathers only once every few years. So it’d be rare to find a completely ‘fresh’ individual like this: more often you’ll see animals with a mix of both old and new wing feathers.