A Small Carpenter Bee (Ceratina sp.) preening its antenna of Fleabane pollen.
Unlike their giant Xylocopa Carpenter bee cousins, which bore significant nest holes in wood, the Small Carpenters prefer to nest within the hollow pithy stems of native plants. Such as teasels, raspberry, sumac, and many others. One of the smallest bees I encounter are the Small Carpenter Bees (Ceratina sp). At under 8mm in length they can easily be mistaken for ants, which I frequently do.
There are 4 Ceratina species identified in Ontario, that look incredibly similar.

Photographed in Markham, Ontario. June 2021.