Christmas tree cultivation species are grown as Christmas trees, although a handful of varieties stand out in popularity. In the United States, Douglas-fir, Scots pine and Fraser fir all sell well. Nordmann fir and Norway spruce sell well in the United Kingdom, the latter being popular throughout Europe. Like all conifers, Christmas trees are vulnerable to a range of pests. The final stage of cultivation, harvesting, is carried out in a number of ways; one of the more popular methods is the pick-your-own tree farm, where customers are allowed to roam the farm, select their tree, and cut it down themselves. Other farmers
Medium tree finch same. This reflects the fact that the two species feed on the same type and size of insect. The beak of the medium tree finch is intermediate in size between the small tree finch and large tree finch. All three species are found in the same habitat. The medium tree finch is threatened by introduced predators such as rats, mice, cats, and the smooth-billed ani, as well as habitat loss, which has occurred through clearance for agriculture. The introduced fly "Philornis downsi" is a significant threat to the survival of this species. Parasitic larvae of this fly live in the