It is a rule of thumb that a hooked bill is used to tear meat to be eaten. Yet, of the hooks seen during last Sunday’s drive, some don’t quite fit the rule.
Perhaps a dozen Turkey Vultures were seen through the day. A migrating species, this bird will soon head south. This one was circling low over a spot on the roadway that had the distinct odour of road kill. The vulture does use the hook of its ivory-coloured bill to tear carrion. 
The Bald Eagle has a hooked bill used for tearing flesh to be eaten. This one is eating a Kokanee, which strikingly, also has a hooked jaw. The males of these land-locked salmon use the hook solely to bite rivals during competition for females. The Kokanee’s hook, seen below the eagle’s, proved an inadequate defence here.
The bill of the Red Crossbill is certainly hooked, although it is not often classified as such. The strangely crossed bill is used to open the cones of conifers so as to extract seeds. A slightly open bill is thrust between the scales of the cone. The bill is closed so opposing tips spread the scales. The head is twisted and the tongue extracts the seed. Crossbills seem to have roughly equal numbers of left- and right-crossing bills. Each is shown here.