Two years ago I watched a pair of Gila woodpeckers, my favorite desert bird, bringing food to their nest in a saguaro. While all of these pictures are of the male, both parents were relentless in caring for their young. Mostly he was doing the sort of things he should, such as bringing a moth (1st picture), a spider (2nd picture), and clearing out debris made by the growing family (3rd picture). But then he brought a small rock, thankfully he realized his mistake before feeding it to the babies and brought it back out. I suspect he must have grabbed for an insect and picked up the rock in the capture, which left enough of a gap for either the insect to get away or fall out in transport.