They are territorial and they patrol areas where females are busily building and provisioning. Carpenter bees are often mistaken for bumble bees, but there are differences. Their nests are mostly underground. Bumble bees spend most of their time traveling between their nest and the flowers from which they obtain food. Carpenter bees are about the same size as bumble bees, but the top of their abdomen is nearly all bare with no areas of yellow hairs and metallic blue-black in color.
Carpenter bees have no pollen baskets on their hind legs - whereas female bumble bees do.
Carpenter bees do not eat the wood they tunnel in, but use the tunnels for rearing the young. The female begins the gallery by drilling an entrance hole usually on the vertical surface of the wood. When the tunnel is about one inch deep, she makes a right angle turn from the initial hole and then tunnels with the grain of the wood. Females select the same sites year after year due to attractive smells and good nesting conditions. Keeping exposed wooden surfaces painted is also a deterrent to attack.