We have four hummingbird feeders up. I refill at least one of them every day. Usually, the hummingbird food is room temperature. Sometimes it’s still a little warm from the stove, but not much. Yesterday we had some left over, so I put it in the fridge. Today I got it out, refilled a feeder, and hung it back up outside. That made me wonder. If hummingbirds drink ice cold nectar too fast, do they get tiny little headaches behind their eyes?