What Is That?

I went for a little stroll around the building at lunchtime today.  I saw a car pull over and a woman get out, holding what looked like a cell phone at arms length as she walked towards a stand of trees.  She'd glance from the phone into the trees as she walked.  She was soon joined by another woman, the driver of the car.  Both women ventured into the fringes of the trees, examining the ground, then the sky, then the ground again.  After about two minutes they walked back to the car and drove off.  I have no idea what they were looking at or for, but they provided me with an interesting distraction for a brief moment.