Not just frost

The temperatures have dipped well below freezing in the past week as evidenced by the skim coating of ice on the fish pond.  I just missed Woodstock's skating episode but his blade marks are still visible.  The morning walk is now over decidedly hard ground although it does still soften up during the day.  Is that something you think of when you are walking?  How hard or soft the ground is beneath your feet? It is something that I have to deliberately think about along with those other subtle but significant physical changes in the natural world. 
The angle and duration of light, the activity of the birds and their specific calls, the color and dryness of the foliage are all seasonal signals. These signals are processed but not perceived until one sits and thinks about them, at least for me.  I think we are all more or less attuned to the changes around us but fine tuning the senses does take practice and purpose as with any worthwhile endeavor.   I notice that the dog's noses are closer to the ground on these cold mornings.  Perhaps to them, the scents are a bit more subtle.  This time of year affords us all the opportunity to refine our senses and pay attention to that which is just as real as the fragrance and color of a rose but which takes a bit more scrutiny and deliberation to discern.  What subtle seasonal change have you noticed in your garden on your daily walk?