I've noticed an interesting psychological phenomenon. You know how, when you step into a dark room from a brighter-lit area, it takes a minute or two for your eyes to adjust so you can see? I've found a similar thing occurs when I go out looking for small things to take pictures of.

At first, I'm looking around intently and I don't see any bugs or crawly things, and I think the outing is a waste. But if I sit quietly and look around for a few minutes, I start noticing them and I realize there's actually lots of them flying around among the plants. It seems the mind is just used to tuning out things on that scale, and it takes a few minutes for it to adjust and start recognizing them. I don't think they're hiding when I come out and then taking wing again once I stop moving. It's a definite feeling of seeing nothing and then suddenly realizing, "Oh, wait, they're actually everywhere."