Eastern Bluebird parent feeds chicks at 13 minutes after sunset

The last feeding of the day for these two bluebird chicks was at 9:01pm local time, 13 minutes after sunset! What's most interesting is that the penultimate feeding (by the female) was a full hour before, at 7:59pm. That means that mother and father birds got a whole hour to themselves in the evening away from the chicks.