The Raven and the Swan

A raven envied a swan the whiteness of her plumage. Thinking that the swan's beauty was owing to the water in which she lived, the raven deserted the altars where he used to find his livelihood and took to the pools and streams. There he plumed and dressed himself and washed his coat, but all to no purpose, for his plumage remained as black as ever, and he himself soon perished for want of his usual food.

Change of scene is not change of nature.