This is the full "marathon" course for the Birkie Trail Run. It includes sections of both the skate and classic ski trails as well as connecting segments of singletrack bike trails.
From the Birkie Ridge parking area, head straight onto the relatively steep climb of the connector trail. The rest of the course alternates between sections of the Birkie skate trail, classic trail, and the CAMBA singletrack trail, and you'll need to keep your head up to avoid missing turns to follow the course when course markers aren't present. This is a great marathon course with a good mix of relatively flat ski trails and somewhat technical singletrack!