Birds also need sunlight to synthesize vitamin D, but their skin is blocked by their feathers. So the chemical precursors to vitamin D are in their "preening oil", a substance they secrete from a gland and rub on their feathers with their beak, an activity called preening. The sunlight hits it and forms the vitamin D, and they end up swallowing enough of it the next time they preen. The preening oil also contributes to the feather's waterproofing and keeps them flexible.
He does very smart critical analysis of video games as a medium, often in multi-hour long retrospectives of entire franchises. They are all split into chapters, so it's easy to watch in parts. The visuals and editing are not very flashy, pretty much just footage of the game he's talking about, but they are so well written and thoughtful I find them extremely compelling. There's also road trip travelogues, but I'm not as into those.
Random interesting thing:
Birds also need sunlight to synthesize vitamin D, but their skin is blocked by their feathers. So the chemical precursors to vitamin D are in their "preening oil", a substance they secrete from a gland and rub on their feathers with their beak, an activity called preening. The sunlight hits it and forms the vitamin D, and they end up swallowing enough of it the next time they preen. The preening oil also contributes to the feather's waterproofing and keeps them flexible.