Thursday, September 07, 2006

In the Blink of an Eye

Hey! What WAS that bird? Just how much credibility can be placed in split-second visual sightings of rare birds, particularly when the identification involves making a decision between two similar species? Much of it depends on the experience of the observer with the two species in question. Much of it also depends on the ability of the human brain to accurately assimilate, store, and recall fleeting images, which probably varies greatly from one person to another.

An interesting discussion on the ID-Frontiers listserv about the identity of a presumed Pacific Golden-Plover (PGP or PGPL) photographed in Utah—a first State record if confirmed—and the difficulty of separating it in the field from the similar American Golden-Plover (AGP or AGPL) resulted in this interesting exchange regarding the ability of observers to make split-second visual identifications in the field:

Excerpted comment by Kevin Karlson:
Without ever looking at plumage, it took about two seconds of seeing the first photo to realize that this was not an American Golden Plover.
Excerpted response from H. Douglass Pratt (Curator of Birds at the North Carolina State Museum of Natural Sciences, and author and illustrator of A Field Guide to the Birds of Hawaii and the Tropical Pacific):
Documenting that first AGP for Hawaii [where PGP is common] is going to be a real challenge, and it’s going to take a lot longer than 2 seconds!
Excerpted reply from Karlson:
As for Doug's skeptical inference that 2 seconds is not enough time to accurately document a sighting, he should take a few minutes and browse through Malcolm Gladwell's recent best selling book "Blink", which is a compilation of psychological studies used to prove the increased accuracy of the brain in processing impression-based information in a very short amount of time. The premise of the book is based upon the incredible amount of information that can be gathered in 2 seconds if we allow our brain to process and store impressions without the usual filters used for analyzing information. By nurturing and using what Gladwell calls the 'adaptive unconscious', these impressions eventually create 'after images' in a part of the brain that can be useful in future comparisons of subtly different shaped birds, such as dowitchers, willets, Western and Semipalmated Sandpipers, Sharp-shinned and Cooper's Hawks, and PGPL and AGPL plovers. The visual recognition of these stored combined impressions for a single species CAN be accessed in two seconds time, and often accurately enough to create a very reliable 'first impression'. Part of this process is intuitive as well, but I am not saying that I stop after two seconds. I studied the photos of the Utah bird for over ten minutes, using shape, plumage, molt timing and feather wear together to complete the picture. I was only saying that my first two second view, based on years of stored physical impressions, was eventually proven to be true after further study.
Excerpted reply from Pratt:
I don't care what that book says, I stand by the statement that 2 seconds is NOT enough to document a golden plover ID! On the other hand, I certainly am a believer in the use of quick impressions in birding. When I look at those "photo quizzes" that are so popular in bird magazines, I find that my first snap judgment turns out to be correct more often than not. But that's a first impression, which then becomes a working hypothesis that is tested subsequently as Kevin describes. But such first impressions don't even approach documentation. For that, we probably have to rely on features that can be perceived equally by all observers.

I do want to check out the Gladwell book, though, because it gets at the heart of how we perceive our surroundings. We all know that snap judgments based on brief glimpses can be just as spectacularly wrong as they can be right, and it seems to me that they are much more likely to be colored by prejudice (read "experience" in the case of birders) than more careful observations. Birders are probably more aware than most that eye-witness testimony is often the most unreliable kind. What we see and what we think we see can be two different things [emphasis added].
In reading this dialogue, I couldn’t help but relate it to the recent sightings of Ivory-billed Woodpeckers, most of which have been fleeting views of birds in flight in heavy-canopied bottomland hardwood forests where Pileated Woodpeckers are abundant. See here for a related discussion.


Blogger Bill Pulliam said...

My feeling is that the blink-of-an-eye ID is not typically adequate to document a rarity, but it can be key to detecting that "something different" that alerts you to the presence of a rarity. Two seconds, however, is not really an "eye-blink." It's actually about as long as (or even longer than) we probably look at a most of the birds we ID before moving on: "Nashville... chickadee... white-eye... magnolia..." When we pick up the "something different" THEN we linger to gather as many details as possible. And when you are dealing with a boldly and distinctively patterned species, you can actually acquire quite a bit of information in just two seconds. Perhaps one should focus on the overall quality of an observation, rather than being obsessed about its length.

September 08, 2006 10:13 AM  
Blogger Bill Pulliam said...

As a side note, I'm really beginning to pine for the olden days when discussions about the theory and practice of field ID didn't always wind up being about one woodpecker in one Arkansas swamp...

September 08, 2006 10:19 AM  
Blogger John L. Trapp said...

I agree, Bill. It really boils down to the ability of the observer to focus on the details of the bird that are most critical for "sealing" the identification, and adequately documenting the field marks that you have seen, whether in detailed field notes, photos, or video, so as to allow evaluation of the record by others. The elapsed time of observation is really immaterial. It's the quality of the information that counts. And nothing counts quite as much as experience in making quick bird IDs in the field. As the old adage says, "Practice makes perfect" (or as close to it as is humanly possible).

September 08, 2006 10:33 AM  

Post a Comment

Subscribe to Post Comments [Atom]

<< Home


The FatBirder's Nest
FatBirder Web Ring