The reason they fly so well in the morning is because theyve had a big feed the previous evening, that is all so time the evening comes they are hungry again hence the reason for poor flying effort of the evening. My birds only go out at afternoons so i feed heavy in mornings and light in evenings as i want there evening exercise to be good. However saying that if i read it rightly your birds are out of sight for an hour, they would be in the training basket if they was mine.