As the clouds took on color nearing sunset, I heard bird calls -- geese, or swans, perhaps -- but I couldn't see their source. They appeared suddenly, winging directly toward my location at treetop height. There were three large birds, dark, with long necks outstretched. As they passed no more than a hundred feet above my head, I heard the whooshing sound of their rapidly flapping wings. From the time they appeared until they vanished beyond another stand of pine took no more than a few seconds, but I continued to hear their calls long after. Now that I've gotten a close look at them, I might be able to find out what species they are. To Google Image Search, at the first opportunity.