Friday, November 24, 2006

Skewing the data

I think "reports since 1944" maps like this one and this one tend to mislead many people.

On these maps, note that all plotted Ivory-bill reports just happen to be clustered within the bird's known historical range.

But note this sentence from Mel White's article:
(Since the discovery announcement, the CLO has received nearly 3,000 reports of ivorybills, some from places as unlikely as Vancouver and Vermont.)
Across this fair country, people are obviously getting a lot of tantalizing glimpses of large black-and-white birds. If the known historical range of the Ivory-bill included Minnesota, I'm confident that we'd currently be treated to "reports since 1944" maps dutifully showing possible Ivory-bill sightings in Minnesota.

Update: John Wall sends along this map, linked from this Stuart Keith article, which concludes:
The ornithological world -- indeed all Americans -- should be thrilled to finally have proof that this magnificent creature the Ivory-billed Woodpecker, long considered a secretive denizen of the most remote southern forests, is neither extinct, endangered, nor secretive, but a very widespread and conspicuous backyard bird over a range larger than ever previously reported!

6 comments:

Anonymous said...

Tom – you are being more than kind to say the maps are “misleading”.

I think we need to fall back on Fitzcrow’s statement about the Luneau video – “not a Pileated” - as the gold standard for assessing IBWO sightings. If someone would plot all of the recent unresolved observations of birds that were “not a Pileated” the map would be a more honest assessment of where the bird might have recently occurred.

It would also help me recruit followers to my emerging Church of IBWO Pantheism.

Anonymous said...

Yes, We all have Gene Sparling to thank for providing us with "proof" the species still exists because he "knows the difference" and "Something big is about to happen."

We're still waiting Gene.

Bona Ditto
" "

Anonymous said...

This just in from Fishcrow.com helps to explain the frequency of IBWO sightings on the maps

"Although I wasn't able to detect field marks in the poor light, I instantly knew it was an ivorybill based on the way it was perched, its sleek shape, and the way it reacted."

Being able to instantly identify IBWOs is apparently a requirement for TBs. Being able to instantly identify BS helps to keep one a skeptic.

Anonymous said...

But, whatever happened to the "real cartoonish" field mark? For me at least, that's the clincher.

Anonymous said...

What are you talking about? These sightings had some vetting. If they were out of range, they were excluded. If they did not have ANY details they were excluded. If the details were contradictory they were excluded.

They are clearly labeled "POTENTIAL" encounters. Are you now saying that these don't even rise to the POTENTIAL level?

Anonymous said...

Doubtful but Openminded,

I could go out right now to the Atchafalaya Basin (an area where IBWO historically occurred), and spot five large, crested woodpeckers and describe them with ambiguous details (red crest with black front; white stripe down the neck; large white patches on wings; direct, not-undulating flight). By your reasoning each of these reports will enter the arena as potential IBWO reports. And in every case, they would also accurately describe a female PIWO as well.

Several years ago when the Pearl River report was still a going concern, people sent in reports from Idaho, Wisconsin, California, and even the Yucatan (as well as the Southeast, of course) of "Ivory-bills." In some cases, they included very good photos of PIWOs. Thus, it is clear that even when seeing a PIWO *very well* people can still be led to believe they are seeing the distinguishing marks of IBWO (the disagreement over what is being seen in the Luneau video also illustrates this phenomenon). The mind plays wonderfully sick tricks on the hopeful.

Without solid, objective documentation (not simply a description or even a sketch), I am now inclined to say that any such sighting simply cannot be accepted, even within the historic range of the IBWO. Any potential observer should know this by now, and make every effort to get *conclusive evidence* before they can expect the greater ornithological/birding community to believe them. There simply aren't enough conservation monies available to waste them on tracking down every damned potential sighting in the historic range of the bird (yet, sadly, that seems to be exactly what is happening). Would-be observers need to understand this. Not accepting a sighting is not a question of doubting the character of the observer (at least, not inherently), it's a question of thoroughness of documentation.

My Two Cents