I also wondered about that track! The one thing that seemed obvious was that you hadn't covered the 13 miles on foot, and that some sort of vehicle was involved to shuttle from place to place.
I had to google Northampton CBC
to figure out what you were up to. What's strange is I walked for three miles on the other side of the river, in a "wildlife sanctuary" (adjacent to Arcadia), and I didn't see a single bird (or any other wildlife, for that matter). But maybe that says more about me than about the birds?