The species was first reported and described by Captain Frederick Wollaston Hutton from the Mount Cook area and Marlborough in 1897, but was put in the genus Pezotettix with some synonyms at that time.

[1] In 2023 morphological and genetic data was used to group all 13 New Zealand endemic alpine grasshoppers into a single genus (Sigaus).

[6] Furthermore, the genetic sequence data (COI & ITS) suggests that B. nivalis comprises northern and southern subgroups, that meet at the Rangitata River in Canterbury.

[7][6][8] Both mtDNA and nuclear markers of southern S. nivalis and S. robustus are very similar with evidence of hybridization between these two species.

[6] Sigaus nivalis is common in rocky montane areas with scattered plants (unlike S. collinus which are mostly found in tussock grass in the Nelson region).

[8] The distribution of S. nivalis is widespread at high elevation in South Island New Zealand from Marlborough, Canterbury and north Otago.

[11] It was observed to feed on plants such as Hebe spp., Epilobium spp., Celmisia spp., Poa spp., Wahlenbergia albomarginata, Anisotome aromatica, Chionochloa pallens, Coprosma pumila, Pittosporum crassicaule, ferns such as Austroblechnum penna-marina, mosses such as Polytrichum juniperinum and unidentified lichens.

[16] However, if further population genetic research suggests that the small, low-elevation forms are distinct from their montane relatives, the conservation status of the low-elevation forms has to be considered threatened by flooding events, land development, weed invasion and introduced predators.

[13] Therefore, the increase in mean temperature due to global warming may cause S. nivalis to lose suitable habitat in the future.