Black bees, formally called carpenter bees, have bare, shiny backs, as opposed to the hairy backs typically observed with bumble bees. Carpenter bees do not live in hives, but drill consistently perfect 1/4-inch diameter holes to lay their eggs in. Carpenter bees also live far more solitary lives than do bumble bees.
Carpenter bees fly faster than bumble bees, but their patterns are jerkier, making them resemble hummingbirds. Carpenter bees spend the cold winter months in old nesting holes, emerging in early spring to find mates. This season sees the most carpenter bee activity, as they seek new domiciles in woods such as redwood, cypress and cedar. If necessary and available, however, carpenter bees drill into pine species and even pressure-treated woods as well.
Because carpenter bees drill very quickly, creating a new hole in mere hours, infestation and damage can occur just as rapidly. Common structural elements affected include eaves and patio covers. One way to defend wood against carpenter bee infestation is to apply paint rather than stain. While these bees do attack stained woods, they do not attack painted specimens because they can't identify it as wood. Pesticide applications do work as well, such as with either cypermethrin or deltamethrin, but as a repellent rather than a poison.