If you think the Sitka black-tailed deer is small, you should see some other, world-wide ungulates. Compared to the rest of its family, it's quite midsized! Don't believe me? I present to you, the pudú.
See if you can spot the pre-orbital glands on the males.
This actually makes the SBTD a pretty good proxy for other species, since the majority of deer species are of roughly equal size (or smaller) and frequently live in environments as topographically and vegetatively complex as the SBTD. It just so happens that most of the other North American cervids (deer) are big animals in comparably simple environments.