The Western Carpenter Ant is found in western North America from British Columbia south to California and Arizona where it has been found primarily in montane forested sites typically at higher elevations. It occurs mostly in stumps and rotting logs, and in human houses (AntWeb 2012
, Greg 1950). This is one of two common species of carpenter ant in the Vancouver area, the other being Campanotus herculeanus
(Higgins pers. comm. 2012).
The Western Carpenter Ant is a polymorphic species that may be brown or black (Lupertazzi and Alpert 2012). These authors provide the following description of this species: "The majors, minors, and females of this polymorphic species are predominantly dull black or dark brown ants. The legs, and portions of the head and the mesonotum, may show some dark red coloration. The gaster has golden appressed hairs with at least a few of these overlapping adjacent hairs. These hairs tend to be half the size of the erect hairs found on the gaster. Other parts of the body also have some appressed golden hairs but these are not nearly as dense as what is found on the gaster. Erect hairs are found on the apex of the scape, scattered along the dorsum of the mesonotum, along the borders of the clypeus and on the top of the petiole. The cheeks and sides of the head are without erect hairs (Mackay)."
Campanotus modoc is cold-tolerant and often occurs at high elevations (Lupertazzi and Alpter 2012). Colonies may be large (up to 50,000 individuals); foraging is most frequent at night (Lupertazzi and Alpter 2012). Nests may start in rotting wood, but as the colony expands tunneling into sound wood will occur (Washington State University Extension 2012).