These buzz pollinators are in the Halictidae family. All of the Halictidae bees are said to be attracted to perspiration, explaining the common name of “Sweat Bee”.
Unlike other buzz pollinators discussed in this blog, bees in the Nomia genus have hard enamel-like bands rather than hairs. The hairier bees in the Lipotriches genus used to be classified as Nomia, but have since been split into their own subgenus.
The males are commonly observed roosting together on twigs. According to AussieBee, there are often hundreds and sometimes thousands roosting together. I only wish that I could find where they roost in my garden!
Below is a video that features footage of a tiny Lipotriches bee foraging in my garden.
Other relevant resources:
YouTube Australian Bee Playlist
Australian Bee Diversity with Dr Tobias Smith