Complex sentence: This species prefers to select the leaves of trees and shrubs with a high protein and low fibre content, but during the winter it may subsist on poorer quality lichens, although it may climb small trees to feed upon leaves that would otherwise be out of reach.
Split into simpler sentences: This species prefers to select the leaves of trees and shrubs with high protein and low fibre contents, but during the winter, it may subsist on poorer quality lichens. It may climb small trees to feed upon leaves that would otherwise be out of reach.