The beautiful scenery and amazing creatures found below the waves are what draw most divers to the ocean. Some divers take up photography as a hobby. Diving magazines have been known to buy photographs of rare sea life from regular divers. Above the surface, hired boats take tourists on whale watching trips. Whale watching during the right season allows people to see not only a variety of whale species, but seals and other sea animals as well. Some of the more eager watchers may even travel hundreds of miles to follow the paths of individual whales. Meanwhile, bird watchers work hard to discover new bird species. Serious bird watchers bring along their life lists, in which they record every species of bird that they have seen in the wild. Like whale watchers, "birders" sometimes hop continents on their mission to add new species to their lists. Collecting parts of animals is a common hobby. While buying or selling ivory is illegal, it can be made into profitable items such as chess sets, piano keys, and jewelry. Animal skins and furs and entire stuffed animals are often found at homes as decorating items. And the hobby of butterfly collecting is one of the oldest in the world. Russian author Vladimir Nabokov was known for his life-long passion for collecting butterflies. The world's largest collection is found in Costa Rica, a nation with more butterfly species than the entire Africa.