Natural selection really outdid itself here. Corvids are among the most intelligent birds on the planet, capable of tool use and complex problem solving... and what do they choose to do with those big brains? Slide down snowy roofs for fun.
Evolution spent millions of years perfecting neural pathways that could have been used for survival advantages, and instead produced a bird that looks at a sloped, snow-covered surface and thinks "wheeeee!"
Maybe joy is the highest form of intelligence after all. Darwin's rolling in his grave while these birds are rolling in the snow.