Birds Rule Again on Mill Creek Climbing Routes Popular rock climbing routes in Mill Creek Canyon in the Bitterroot National Forest are closed in an annual restriction to allow birds to nest in the area. Most of the closures are on the north side of the canyon, where established nests of raptors such as falcons will be occupied by the birds and, more importantly, their eggs. Tod McKay of the Bitterroot National Forest (BNF) said the closure is the same as last year and included the "Pie for Strength" climbing route, along with some south side routes that were added last year. Those nests will be checked this spring to see if they're still being used. McKay said if the nests are abandoned, the restrictions will go away.