The most explanatory environmental variable for FPT was snow
depth, with slow crossers showing evidence for faster FPT (i.e., positive
coefficient) in deep snow than normal crossers (Table 3). Slow crossers
exhibited evidence of shorter FPT for all other environmental coefficients
than normal crossers, except for distance to rivers, where they had
longer FPT the further from rivers they were (Table 3). Most striking
of these results is that, even after taking account of a wide-variety of
environmental variables that could affect FPT, the distance to the road
and whether an individual was classified as a slow or normal crosser
still were the most explanatory variables of FPT, indicating the strong
role the road played during autumn migration.