Kate enlightened me to an interesting quote from legendary birder David Sibley. The quote was included in the book Blink by Malcom Gladwell, which focuses on the importance and efficiency of split-second decision making.
"The ornithologist David Sibley says that in Cape May, New Jersey, he once spotted a bird in flight from two hundred yards away and knew, instantly, that it was a ruff, a rare sandpiper. He had never seen a ruff in flight before; nor was the moment long enough for him to make a careful identification. But he was able to capture what bird watchers call the bird's 'giss' -its essence- and that was enough.
'Most of bird identification is based on a sort of subjective impression- the way a bird moves and little instantaneous appearances at different angles and sequences of different appearances, and as it turns its head and as it flies and as it turns around, you see sequences of different shapes and angles,' Sibley says. 'all that combines to create a unique impression of a bird that can't really be taken apart and described in words. When it comes down to being in the field and looking at a bird, you don't take the time to analyze it and say it shows this, this, and this; therefore it must be this species. It's more natural and instinctive. After a lot of practice, you look at the bird, and it triggers little switches in your brain. It looks right. You know what it is in a glance.'"
This is spot on. Good birding!