A Clean Required

This is one of the (many) snail trails in the dust on my garage door.
What I want to know is how some of them are like this and are just 'There' ....... no contact with the edges  of the door or other tails.
Are they airborne in the wind and blown off again?
Should I buy a trail camera and try to catch one in the act? - or should I just clean the door and to hell with it?

The wind has been picking up during the course of the day and each time I have gone out to the garage to work at the lathe the pile of leaves coming in to join me has increased. 
I understand that trees are coming down not too far away and things are not set in improve any time soon.

We got an invitation to join a video call from No1 son and family along with Bags.
With SWMBO and I both using our phones there was a problem with microphone feed back so I had to try and set up up on my 'emergency' laptop (the one being help together with tape and clamps) because it has a camera and my new one doesn't (I am sure there is a webcam somewhere in the house but I am damned if I can find it).
After the system trying to tell me that I was trying to use the wrong e-mail address and then refusing to accept the (saved) password I had to start from scratch setting it all up again. Once I did get it all up and running the first thing Bunny did was run over to give me a kiss. Very good of her, but she needs to learn that kissing the screen means that I can't actually see her. She will learn though - bless her.