It looks like more than just 2 of them. Look closely at the 3rd and 4th photos.
Just for fun, if we take the idea seriously that these are somehow alien craft, (even though it bears a striking resemblance to an inverted cocktail strainer) what could we imply from that? Bilateral symmetry? A preference for using one side over the other (right vs left 'handed')? Specialized function?
Taken at face value, remaining in the same area would imply searching for something, so the arms might be part of a directional sensor array. So, did the kids wander away from the off-planet picnic? Or be there dilithium crystals 'neath those trees? Where is this supposed to be? Any word on the geology of the area, anyone?