Eirik Blom article on IBWO skepticism

A couple of years ago, this article by the late Eirik A.T. Blom was published. Please read the whole thing--I think it is as relevant today as it was two years ago.

Here's a key snippet:

-----
....What that means is that there are not a couple of last, lost ivory-billeds that have been hiding for the past 50 years. It means that there have been generations of birds, birds breeding and successfully raising young. Given failures, unexpected deaths, and natural mortality, at least 10 generations and probably four times that. And there have to be enough birds to breed without inbreeding themselves out of existence. We are not talking about a couple of woodpeckers, we are talking about a bunch of them. And where have they been hiding? One bird might elude detection for a while, but not clumps of them.
-----

Who has visited?

In recent days, I know that this site has been visited by David Sibley, Jerry Jackson, Richard Prum, Mark Robbins, John Fitzpatrick, David Luneau, and many others. Through the back channels (email and/or phone), I've had very interesting two-way communications with all six of the people that I've listed.

As of August 8th, Jerry Jackson wrote "I don't mind if you say that I withhold judgment as to the validity of the recordings until I hear them, or that I have serious questions about the original data that were presented in Science."

I've asked them all for comments and feedback, and they've been great. As I've learned new things, I've incorporated them into my blog. That group of six people has supplied many comments along the lines of "I think your blog is fair and accurate", "your skepticism is healthy", and "keep it up". Of course, as you may imagine, not all of them agree with my conclusions.

IBWO: could all those sight records be mis-IDs?

In Cornell's paper, could all seven of the sight records really be mis-IDs?

I think the answer is "Yes".

Remember, Cornell described them as "Fleeting Glimpses". These were typically brief, flying views, at a distance and/or with the naked eye.

As Gallagher relates in "The Grail Bird", page 164: "If you want to see an ivory-bill bad enough, a crow flying past with sunlight flashing on its wings can look pretty good.

I think an honest question-and-answer like this could follow most/all of the reported sightings.
---
1. Did you see the underwing well enough to describe it correctly?
Answer: No

2. Did you see the white dorsal stripes well enough to describe them correctly?
Answer: No

3. Did you see the bird well enough to describe the white neck line that ends before the bill?
Answer: No

4. Did you see the bird well enough to describe the pale bill?
Answer: No
---
In my opinion, if you answer "No" to all four questions, you didn't see an Ivory-bill really well. I can't imagine a state records committee that would approve such a sighting.

In the book Sibley's Birding Basics, a couple of key paragraphs on page 41 may be relevant:

---
...An observer might see something intriguing, say a large falcon flying away, and jump to the excited conclusion that it could be a Gyrfalcon, a bird normally found in the far north. The next step should be to pause and start from the beginning, looking at each characteristic objectively, but too often the overexcited birder tends to stick with the first impression and simply tries to confirm the identification as a rare species. Often, a very brief sighting does not allow any more detailed study, and the observer might choose to emphasize anything that can tip the balance toward the desired identification: "Yes, it did look long-tailed; yes, it was very dark; it just didn't 'feel' like a Peregrine,", and so on. Other poorly seen field marks that point toward a Peregrine Falcon--perhaps it looked long-winged, or seemed to have a contrasting white cheek--are then ignored.

This problem can result in a sort of "group hysteria" when large numbers of birders look at the same bird. The suggestion by one person that the bird is a certain species forms an expectation for everyone else, who then looks only for field marks to confirm the "expected" identification. In one very well documented case in California, the first state record of the Sky Lark (a Eurasian species) was misidentified for days, and by hundreds of people, as the state's first Smith's Longspur. The two species have a superficial similarity but are not even in the same family and can be distinguished by dozens of features. The initial observers expected a Smith's Longspur to show up in the state and never considered the Sky Lark as a possibility. Most of the people who went to see this bird over the next few days had the same expectation, augmented by the knowledge that they were looking for a "confirmed" Smith's Longspur.
---

From quotes I've read, in the spring of '04, it seems like conditions were ripe for mis-IDs as discussed in the Sibley paragraphs above.
-----
Ron Rohrbaugh said, "It was an absolutely electric time. To think that around every bend, behind every big cypress, there could be an ivory-bill."
-----

I'm not up on a pedestal saying that it couldn't happen to me. A painfully embarrassing case occurred when I was glassing for wildlife from a high hill in Alaska one fall. With a previous sighting of distant black wolves under my belt, I again saw some slow-moving black dots in the far distance. After I shouted to my companions that I was seeing wolves, we discovered that the black dots were actually ravens.

It happens, even to the "experts". If you combine a brief, distant glimpse of a flying bird with the expectation that the bird may be an already-confirmed rarity, you have a potent recipe for a mis-ID.

Just how wary was the IBWO?

In "The Grail Bird", page 248, it says:
---
[John Fitzpatrick] also suggested that perhaps during the years when the birds were hunted extensively by collectors, only the quietest and wariest individuals in a few remnant forests survived to pass on their genes to future generations. This could explain why it is so difficult to find an ivory-bill and record its calls. Perhaps all the noisy and approachable ones were killed off a century ago.
----

This is a very key issue. If the Ivory-billed woodpecker exists today, how wary is it likely to be?

Let's start with a snippet from Allen and Kellogg's 1930's paper:
----
The destruction of Ivorybills by the Indians in the early days is mentioned even by Catesby, in 1731. In his original description of the bird, "Pious maximus rostro albo," he says, "The bills of these Birds are much valued by the Canada Indians, who made coronets of 'em for their Princes and Great Warriors by fixing them round a wreath with the points outward. The Northern Indians, having none of these Birds in their cold country, purchase them of the Southern People at the price of two, and sometimes three, Buckskins a Bill." Thus early did commercialization of the Ivorybill start, and the price on its head has continued to the present day.
----

Ok, so there was hunting pressure on Ivorybills for at least 200 years prior to the 1930s.

Later in that same 1930s paper, Allen wrote:
---
This same sedentary habit, once a community has been located by collectors, has made it possible in the past to exterminate local groups of Ivorybills, and this may well have happened even in the name of science.
---

In other words, even when other Ivory-bills in the community were shot, the remaining Ivory-bills didn't turn canny and flee. They stayed around and were shot as well. In 1944, the last authenticated U.S. Ivory-bill was also half-tame, allowing Don Eckelberry to watch and sketch her at a roost-hole for two weeks.

In the last 60+ years, we have no records that anyone's shot an Ivory-bill. Any remaining birds faced no more hunting pressure than a Downy, Hairy, or Pileated Woodpecker. I see no reason why the Ivorybill would stay half-tame through over 200 years of hunting pressure, then make a quantum leap to ultra-wariness during 60+ years of no hunting pressure.

In short, I see no reason that an Ivorybill in 2005 would be any more wary than an Ivorybill in 1935.

Some more stories from the waning days of the Ivorybill:

According to "The Grail Bird", page 8, it says that the Ivorybill was believed extinct in 1920. In 1924, Arthur Allen, while traveling in Florida, checked out an alleged ivorybill sighting and managed to locate an active nest. One day while he was away, a couple of local collectors shot the pair of woodpeckers-legally. In the 1930s, a man named Mason Spencer told the director of the state Department of Wildlife and Fisheries that he'd seen ivorybills. The book goes on:
---
Incredulous, the director drew up a collecting permit for Spencer and challenged him to prove it. A short time later, Spencer came back with a freshly shot ivorybill, and as legend has it, flung it down on the director's desk.
---

Again, this is evidence that when the Ivorybill was rare but not extinct, it could be seen well. People walked right up and shot them, and it didn't take 20,000 hours of intense field work to get some glimpses of something that may or may not be the bird.

Bottom line: I think it's likely that the Ivory-billed woodpecker is extinct.

More on the alleged IBWO audio evidence

Last week, we read this in the New York Times:
-----
"The thrilling new sound recordings provide clear and convincing evidence that the ivory-billed woodpecker is not extinct," Dr. Prum said in a statement.
-----
The headline read "Vindication for Ivory-Billed Woodpecker and Its Fans".

David Luneau (of the search team) tells us that these recordings are actually not new, and to the team of authors, they are not convincing proof.

David wrote this a few days ago:
----
Interestingly, our team of authors does not agree on the origin of these sounds, which is why we didn't put them in our paper in the first place. We maintain that the acoustic information, while quite interesting, does not reach the level we require for "proof".
----

I don't know why Prum and Robbins would be skeptical on the evidence in the original paper, then suddenly become believers after hearing some audio. As far as I know, Jerry Jackson, David Sibley, and Kenn Kaufman are still among the skeptics.

Here's what Cornell wrote in their paper:
-------
Double-knock sounds strikingly similar to Campephilus display-drums were recorded on several of the ARUs and appear to be concentrated in the vicinity where drumming was heard on 9 November 2004. We cannot positively associate these recorded signals as belonging to ivory-billed woodpecker, however, and several seem out of context. Series of nasal calls closely resembling those recorded by A. A. Allen at the Singer Tract in 1935 were recorded at two places in the White River National Wildlife Refuge, but these may have been given by blue jays (Cyanocitta cristata, a notorious mimic). Certainly, if blue jays do mimic ivory-billed woodpeckers in this region, the implication that a model exists bears investigating.
-------

Again, they say that multiple series of kent calls may have been given by blue jays.

Update: In Jerry Jackson's book "In Search of the Ivory-billed Woodpecker,” page 182, you’ll find his account of hearing a Blue Jay give this call in New Jersey--far outside the range of Ivory-bills. This call is evidently part of their normal repertoire, meaning that they can produce a series of "kent" notes without ever having heard an Ivory-bill or an Ivory-bill tape.

Regarding the double-knocks--I would very much like an explanation for that "several seem out of context" remark. To me, that sounds like they may have heard double-knocks while also hearing diagnostic sounds of other birds (for example, maybe Pileated Woodpecker vocalizations).

I really think that Prum, Robbins, and Jackson should un-withdraw their rebuttal paper! In this web-enabled age, I think the ultimate truth is likely to arise much more quickly if these kinds of debates are free and open to the public.

===========
A couple of additional items:

1. Take a look at what's going on--they're now using herbicide to kill a hundred or more healthy trees, in an effort to indirectly feed a species that (in my opinion) has likely been extinct for decades.

2. Laura Erickson has been maintaining a nice page of links about the Ivory-billed woodpecker.