Many
Willow Cabbage galls are still on the willows. Now that the normal leaves
are all gone, you can see them from some distance away and notice how many
there are.
They are caused by the grub of a fly that injects an egg into the growing tip of the willow. All further woody growth stops and the leaves pile up on top of each other making a sheltered place for the grub to develop and emerge as an adult fly.