The carpometacarpsus in the Messel specimens shows similar proportions to modern swifts, but with different osteological details.

Although the legs of modern swifts are highly reduced, the tarsometatarsus in these species is proportionally much longer and more slender than in Scaniacypselus.

[1] Wing shape is already indicated to have been relatively short by the osteology, which is confirmed by specimens preserving soft tissue such as feathers.

These specimens show that the wings of Scaniacypselus weren't as long and narrow as in modern swifts of similar size.

[3] When first described researchers noted that the taxon shares several key characteristics with crown group swifts, consequently placing it in the subfamily Apodinae.

[2] The discovery of multiple additional specimens of S. szarskii however highlighted previously unknown features that set it apart from crown-group swifts.

[1] Aegothelidae (Owlet-nightjar) †Eocypselus †Aegialornis †Primapus †Parargornis †Argornis †Cypselavus †Jungornis †Eurotrochilus Crown-Trochilidae (Hummingbirds) Hemiprocnidae (Treeswifts) †Scaniacypselus Cypseloidinae Apodinae The broader wings of Scaniacypselus clearly show that the taxon is much less specialised than modern swifts.

However their feeding range was likely much more extensive than that of the modern treeswifts, which are limited to hunting grounds close to the forest canopy.

In its hindlimb proportions Scaniacypselus is much more similar to treeswifts and hummingbirds as well as other perching birds than to true swifts.

Specifically, the ability to perch like hummingbirds and treeswifts suggest that the animal was much more arboreal and nested in trees, spending much less time in flight than true swifts.