These are obviously bird tracks. Notice how the two inner toes on each foot stick together while the outer toe is by itself. This is characteristic of the Corvids- ravens, crows, jays and magpies. The size of these tracks show that a gray jay left these tracks in a dusting of snow.
Also look for ptarmigan scat and snow roosting sites where you see a lot of ptarmigan activity.
Without a scale it may be difficult to identify this as a marten trail. Always put a scale in a photo if you are using it to document tracks and trails.
You can make out the five toes. This is about as clear as the tracks will get as Marten feet are heavily furred.
This lynx was breaking through a thin, weak crust but not sinking too deep. The snow is over 4 feet deep.
This one plunged, but not deep. It then lifted itself out of the snow with its wings and took off with a powerful stroke.