Black items get lost easily in a shady place if the sun is shining. When the iris' of your eyes get small, things disappear on you. Stage magicians depend on that as a matter of fact.
Long ago, maybe 11 years back, I was on a solo hike on top of a bluff chasing 2 geocaches. I had my work cellphone in a holster clipped to my backpack shoulder strap, thinking it was secure there. Well at one of my stops where I retrieved a geocache, I took off my pack and and the holster came off the strap. I did not discover that fact until I had reached the end of the trail and was about to descend the bluff to where I parked. I had 5.5 miles walked showing on my gps. I was on-call for the weekend, I really needed to find that thing. I back-tracked through a mob of mosquitos as the sun got lower in the sky. I did figure it was most likely at a spot where I stopped and bent over a lot. I spotted it after walking back 2 miles. I was over 9 miles descending the hill. Yes that is my personal record hike. I was as spent as could be. I think the mutant mosquitos were actually attracted to the DEET spray I kept applying. The sun set as I drove away. I was desperate for some food and sleep, but had to go 30 miles to get home. Ahh, good times.