My wife Julie and I regularly visit the Rio Grande Valley in Texas and look for Parauques, a close relative of the Common Nighthawk that roosts on the ground under shrubs and bushes during the daytime. Their cryptic camouflage makes them very difficult to find even when you are looking at known roost sites and you KNOW they have been there. Fortunately, Julie has an uncanny knack for detecting their plumage in the lattice of sticks, leaf litter, shrubs and shadows of the valley. We go to known roost areas and she can find them quickly. We know their preferred habitat, and she spots them before anyone else.
This year I went to a spot where we know them to roost for years, and they had been seen there an hour earlier. I looked and looked and looked and could not find them. Concluding that some idiot had gone too close and flushed the birds, I was about to give up after twenty minutes when I spotted one, about two feet away from me off the trail. Some more people came looking and could not find any either. I was about to point out the one bird, when I got an angle of view and enough light to see a second. The people could not see either until looking right at them for minutes. Several more people came and I was about to point out the two paraugues, when I shifted position enough that I spotted the third. I could not believe that the three had been there the entire time, within 2-6' of me at times. They are various shades of brown, but the patterns are so rich and varied in tone that they blend in perfectly to a ground cover of dried sicks and shadows.