But there certainly are a lot of them around here. There are large heronries in several Lower Mainland municipalities, and if you want to add this bird to your suburban Backyard List, install a pond and fill it with koi, the more expensive the better, and voila.
A much less often seen species is the Black-crowned Night-Heron. Night-Herons (note the hyphen) are a widespread group whose monophyly is uncertain and relationships are unclear, as discussed in a recent post in Catalogue of Organisms.
Southern British Columbia is at the northern extreme of the Black-crowned Night-Heron's range. It is considered rare in BC, and there are only a few records of it having bred in the province, perhaps only two -- both being on Reifel Island (Campbell et al., 1990). There is a small group that winters at Reifel. The birds can sometimes be found just inside the gate on the north side of the path, or in the brush at the the edges of the first large slough. Three were visible in the bushes very close to the split-rail fence across from the warming hut on our recent visit. If you want to work hard to add a BCNH to your list, go look somewhere else.
Campbell, R.W., N.K. Dawe, I. McTaggert-Cowan, J.M. Cooper, G.W. Kaiser and M.C.E. McNall. 1990. The Birds of British Columbia. Vol. 1. UBC Press. 514 pp.