I do not think it was her breath...look at how it is behind the wood rails of the fence..not in front of it at all.  Just my two cents.

Carol B.

It looks like it could be from you breath.  Make sure to hold it when taking photos.  You can do a little test while in the field by exhaling during a photo, and holding it during a photo, campare the two, you will see what I mean.  I had to learn the same way. Ali