Final answer:
You are most likely in the Hudson Bay Lowland muskeg when observing a Sandhill Crane, Great Sundew, and Lesser Yellowlegs, as this is a wetland habitat that supports such diverse species more so than tundra, peatland, or fens.
Step-by-step explanation:
If you observe a Sandhill Crane, a Great Sundew, and a Lesser Yellowlegs, you are likely to be in a habitat that combines wetland characteristics with the presence of a variety of birds. Considering the ecosystems mentioned and the species observed, the Hudson Bay Lowland muskeg would be the most probable answer. This is because a muskeg is a type of wetland found typically in the boreal regions, which includes both evergreen trees such as spruce and pine, and a range of mosses and lichens that resonate with the habitat where you would find these species.
Comparatively, while the tundra contains lichens and grasses that could support some bird life during the summer, its colder, drier, and less diverse environment compared to a muskeg makes it a less likely habitat for the Great Sundew, which is a carnivorous plant more associated with boggy conditions. The Lesser Yellowlegs, commonly found in wetlands, would also be better represented in the Hudson Bay Lowland muskeg environment. The other listed options like peatland, fen, and conifer-dominated forests are not typical habitats for these species either.