When it comes to plumbing the depths of bird identification, I find discussions about the psychology of field craft as, and occasionally more, fascinating than arcane discussions of cryptic field marks. How our brains process birds in the field based on often incomplete and misleading information, and the potential pitfalls therein, is something I think about on many occasions, often in response to my own limitations as a birder.
That's apparently something David Sibley thinks about too, but his insight comes from the perspective of a field guide author, tasked with taking that frustrating incompleteness in the field and turning it into something identifiable. His blog, already a must read on the web, allows him the space to muse about the two stages of field identification, discovery and confirmation.
A Lesser Black-backed Gull among Herrings and Ring-bills, Chatham Co, NC. Spotted, initially, in discovery phase. photo by Nate Swick
We’re in discovery mode when scanning a flock or searching through a habitat looking for a certain species, or at the moment when a bird pops up in a bush and we say “Hey, is that a..?” Field marks useful for discovery are broad and generic, often average differences that can be seen at a great distance or assessed instantly to weed out the obvious non-candidates. Once a candidate is found we switch to confirmation mode and look for more objective details.
There's much much more and it's great, insightful, stuff. Check it out.