You appear to have the city of Chilliwack itself labelled as "Tzeachten" on your inset. Tzeachten, which I had never heard of until now, is just a small First Nation outside the city, and certainly not all those polls.
That's just part of Chilliwack. The inset was labelled as Tzeachten by Elections BC, so I assumed that's what the region was called: http://www3.elections.bc.ca/docs/rpt/2009GE/CHH.pdf
You're right about the labelling; weird.
According to the census the reserve is only about a quarter aboriginal by population, so you have to be careful about assuming who the Natives are voting for.
