Final answer:
The Nightwings likely lived in a high altitude environment akin to mountains before moving to the rainforest, but without the specific literary context, this is speculative.
Step-by-step explanation:
The Nightwings mentioned here appear to refer to a group in a literary context rather than a biological or geographic one. However, given the information provided and common knowledge of habitats, if the Nightwings were a species or group of beings from a story, previously living in a high altitude environment such as the uplands in Utah, and are currently residing in the rainforest, it suggests that they have experienced a dramatic change in their environment. The information provided doesn't directly answer which specific habitat they lived in before the rainforest, but if we consider 'high altitude uplands' as a clue, it would closely resemble a mountain region. As such, the answer may be (a) The mountains, since this option is most consistent with high altitude living conditions. However, this is speculative without a direct reference to the Nightwings' original habitat in the question's literary source.