Is the Ivory-billed Woodpecker still with us?

April 11, 2022 • 10:00 am

UPDATE: I have removed the photos from the new paper as the authors have copyrighted them and won’t give me permission to use them. , but you can see them at the site.

 

In 2005, a paper in Science by Fitzpatrick et al. produced a flurry of ornithological excitement. The paper (click on screenshot below) adduced evidence that the Ivory-billed Woodpecker, Campephilus principalis—thought to have been extinct in the US (and elsewhere) since about 1940was actually persisting in wet lowland forests of the South.  This was based on sightings and recordings of calls, but the photographs weren’t that convincing. Nevertheless, the authors declared that the bird persists: click on the screenshot to read.

This magnificent beast, the third largest woodpecker in the world, used to have a fairly broad range across the South, but was limited to wet lowland forests with very old trees. Loss of habitat caused a big popuation decline, and fewer and fewer sightings were made. Here’s a photo of a male from Louisiana in 1935, and another, showing both sexes, is colorized below:

A colorized rendition of a photograph taken by Arthur Allen of an Ivory-billed Woodpecker at a nest in Louisiana’s Singer Tract, 1935. Photo: Cornell Lab of Ornithology

As you can see from the second photo, one distinctive feature of this bird is the sexual dimorphism in crest color: males have red crests and females black ones.  Ivorybills also have a distinctive white “saddle” on their back, and white patches on the wings. These features, and the larger size of the Ivory-billed, distinguish it from a similar species, the pileated woodpecker (Dryocopus pileatus), the largest woodpecker known to exist in the U.S. (many of us have seen them).

Here’s a comparison of both species that I showed when I wrote about the Ivorybill in 2010. Note the white saddle of the Ivory-billed, absent in the pileated, and the sexual dimorphism of the crest. Also, there are differences in facial coloration. It is the superficial similarity of the ivory-billed to the pileated that has led people to declare that, after seeing the latter (they co-occurred), the former was still around.

Audubon’s painting:

And a drawer of preserved ivorybills from Harvard’s Museum of Comparative Zoology (again note the sexual dimorphism):

Ivory-billed woodpeckers at Harvard’s Museum of Comparative Zoology. Image: Damir Frkovic © 2009/Small Change Productions

But over the years after 2005, repeated forays into Louisiana bottomland—the people who see these things tend to keep the locations secret as the places would get overrun with birders and gawkers—failed to turn up convincing evidence of the bird (a really good couple of photos or videos would do). And despite a movie made about the “rediscovery”, Ghost Bird (and a presentation on YouTube), people lost confidence that this elusive bird was still around, and interest waned. Except among a small group who have just published a paper.

On September 29 of last year, the U.S. Fish and Wildlife Service declared the Ivorybill, along with 22 other species, extinct.

And so, apparently, this woodpecker joined the passenger pigeon and Carolina parakeet as one of America’s most famous extinct bird species. It was declared an ex-woodpecker, singing with the Choir Invisible.

But wait—not so fast! I was alerted to a new paper by this tweet from Matthew, linking to a paper that gives pretty convincing evidence that the Ivory-billed Woodpecker is still around, though not numerous.

I’ve read the paper, as have two of my ornithological colleagues, and both declare that the evidence in the paper below is fairly strong. Click on the screenshot to read it, and download the paper here.  Do note that this is an unpublished manuscript, and appears on bioRχiv. It must be reviewed and published before its credibility can increase.

What’s the evidence? Well, the authors scoured a 93 km² (36² mi) area of Louisiana bottomland and mosaic upland for ten years, using both high-flying drones (for 3 years) and trail cameras, and came up with a number of photos, as well as recordings and videos (the photos are the evidence they present. There were 438,000 camera hours of watching and about 1590 drone flights. The evidence, as they say above, is multifarious. It includes these features:

PHOTOS REMOVED AT AUTHORS’ REQUEST

1.) Morphology:  Photos show the white saddle and a dimorphism of crest color, though the photos are admittedly not great. Here are a couple from the paper (captions from the paper; also, see the paper for the videos). I’ve put an arrow by the white saddle:

Enlarged: left column is an Ivorybill photographed years ago in Cuba (where they once lived as well), and the right column shows a new photo and enlargement:

The bird they photographed is also larger than related species photographed on the same tree. Here’s another photo.

There are also apparent differences in crest color seen in some photos like this one, with one member of a pair having a red crest and the other a black one:

 

2.) Behavior. The ivorybill has a different morphology of feet and legs from that of other woodpeckers.  This results in a very different stance of the ivorybill when it’s sitting on a vertical trunk.

From the paper:

Most intriguing is that these images depict the distinctive morphological adaptations of the feet and legs of Campephilus woodpeckers as compared with Dryocopus woodpeckers like the Pileated Woodpecker (33). The phenotypically similar Pileated is one of the most unspecialized of the truly arboreal woodpeckers, while the Campephilus woodpeckers are characterized by pamprodactyly, a pedal morphology that enables the forward rotation of all four toes (33). The specialized modifications in the highly arboreal Ivory-billed Woodpecker are not so much in the structure of the toes as in the position of the legs. The feet are held outward from the body and are directed diagonally upward and sidewise (Figure 7), with both feet wide apart and more anterior relative to the body (33, 34). Usually the angle between the tarsi and the horizontal plane is ≤45˚, and often seem to be pressed against the tree trunk. This is very different from the condition seen in most woodpeckers, as, for example, the Pileated Woodpecker, where the legs are held more or less beneath the pelvic girdle, the joints are fully flexed, and the tarsi are held well away from the tree trunk. This generally results also in a more obtuse angle of the intertarsal joint (where the leg bends between the tibiotarsus and the tarsometatarsus), and is evidence of the better scansorial adaptations of the Ivory-billed Woodpecker compared to the PileatedWoodpecker (33). This obtuse angle is visible from a distance, is readily seen in our images (Figures 6, 7), and can be a useful identification clue in situations where lighting or distance makes it hard to observe plumage details with clarity (35). Combined with feet extended diagonally upward and to the side of the body, the stance of the birds appearing here are consistent with that of a Campephilus sp.

In other words, the ivorybills show what a feminist ornithologist might call “birdspreading”, with a wide stance, legs angled upward (not below the pelvis, as in the pileated), and feet forward. Two photos (A and D below) are from this study. No other woodpecker stands like this.

Fig. 7: Comparison of photographs taken of apparent Ivory-billed Woodpeckers in Louisiana from this study (A, D), with a colorized Ivory-billed Woodpecker, also from Louisiana, but taken by Arthur A. Allen in 1935 (B), and a Pale-billed Woodpecker (Campephilus guatemalensis) are directed diagonally upward and sidewise, with both feet wide apart and forward. The angle between the tarsi and the horizontal plane is ≤45˚ and there is an obtuse angle of the intertarsal joint. Photos (B) and (C) are from the James T. Tanner, and the Arthur A. Allen papers, respectively, courtesy Division of Rare and Manuscript Collections, Cornell University Library.

I encourage you to watch the two video clips (successions of trail-camera photos), which you’ll find here.

There are several other behavioral indices that these are ivorybills.  Comporting with historical observations, the birds seen recently fly high and far, having big home ranges. They are also fast. All three of these features differ from the pileated, whose flight is quoted as being “rather slow, but vigorous and direct.”

Finally, while pileateds forage alone, the authors of the present paper saw three of the putative ivorybills foraging just a few meters apart—perhaps a family group. This of course is one anecdote, but it adds to the evidence.

The authors conclude (and I agree, along with some birders), that they have indeed seen living individuals of Ivory-billed woodpeckers.

But some ornithologists aren’t convinced, and for good reason: the evidence, while pretty good, is not strong enough to be dispositive. When I asked my colleague Steve Pruett-Jones what it would take to convince ornithologists that the species isn’t extinct, he said this:

Well, I’m not really sure. It would vary with the person I guess. Clear, unmistakable photographs or a video would do it.
The paper in question has not yet been peer reviewed and so there may be additional criticisms that come to light.
The criticisms of the earlier reports (over the last 10 years) were generally along the lines of ‘without a clear photograph, you can’t completely rule out a pileated woodpecker’.
This criticism or skepticism is also rooted in the belief/assumption that there are so many birdwatchers now, and there are so few large intact flooded areas where the bird could survive, that if it was still alive, it would have been seen by more people.
Steve, who is fairly convinced by the evidence, also sent me a link to the only summary of this new paper I’ve seen, from revkinbulletin.  It does give criticisms, including some by ecologist Stuart Pimm. They don’t dismiss the evidence, but Pimm argues that the amount of habitat left for these birds is so small that some individuals must have crossed open areas and been seen by birders.

The conclusion is that old chestnut of scientific conclusions: “More work needs to be done.” But one thing is for sure: this new work (which is ongoing) will make birders think twice about declaring the ivorybill extinct, and will spur new efforts to find it. Of course without a concerted effort to save or increase the habitat (wet bottomland forest), seeing the bird is not the same thing as saving it.

h/t: Steve

28 thoughts on “Is the Ivory-billed Woodpecker still with us?

  1. I sure hope these reports can be verified. Physical evidence such as a feather or excrement would be convincing for its DNA value, but would also be an unlikely find in the Louisiana forest.

    1. I am not an ornithologist, I’m someone that spends lots of time in one of the most remote river basin in Louisiana. I have heard the double knock on 3 occasions. The Atchafalaya Basin is accessible by boat only and is a place that has a few stands of old growth cypress left. I have not seen it but I have definitely heard it.

  2. Very interesting and compelling. I am hopeful that these birds are still with us. Even if there are some surviving, there might not be enough of them left to ever again be firmly established. Your closing statement says it well.

  3. …and there are so few large intact flooded areas where the bird could survive, that if it was still alive, it would have been seen by more people.

    Maybe it was seen by more people, but all those people told themselves that they couldn’t possibly have seen it.

    1. I just saw one at our suet block yesterday; yes, they are rather awesome. We have a pair that I see fairly often, though I hear them a lot more than see them. Thanks to this post, I’ll be able to tell the male/female apart now.

      1. “…though I hear them a lot more than see them.”

        That’s what is weird and suspicious about this study. It is far easier to record the call of a big woodpecker than it is to get a picture of one. Why weren’t recordings presented as evidence in this study?

  4. Well, I’ll be. That’s some heartening news. I’m cautiously optimistic and hope the on going work proves the woodpecker is still with us.

  5. Fannn-tastic! Tangentially, this seems like a good place to ask a general woodpecker question that I wondered last week: Do young woodpeckers learn from their parents by observation, or is pecking wood to obtain food hardwired?

  6. I dearly hope this is true, but generally for birds like this, the distinctive calls are the first sign of the bird. I find it strange that Exhibit 1 of this paper is not a recording of its call.

    1. OTOH, after all they’ve been thru, could it be that the surviving clade(s?) have survived partly from not vocalizing? The description I recall was that they sounded like a toy horn or a tin horn.

      1. That’s possible, I suppose, but it seems unlikely since no one hunts these. They don’t just call, they also have territorial drumming, if they are like their Latin American congeners, the Pale Billed Woodpecker and the Crimson-crested Woodpecker. The distinctive double tap of these two species travels far. I usually hear them before I see them, and often I hear them but don’t see them at all.

  7. If you were to ask me which bird I would most like to see in the world, I would answer without hesitation: ivory-billed woodpecker. When I was younger, I fantasized about finding one, even though I don’t live in the area where the birds used to occur.

    I remember well when, in 1999, the incredible news came in that a forestry student had seen a pair of ivory-billed woodpeckers in the Pearl River area of Louisiana while turkey hunting. He was deemed a very credible observer by the bird people who talked to him. The date was … April 1 (!). Exciting … but, despite searches, the sighting was not confirmed. After a while, the student refused to talk any more about the matter. Then, in 2004, a kayaker named Gene Sparling claimed to have seen a big woodpecker that fit the description of an ivorybill in Arkansas. Two “bird people”, Tim Gallagher and Bobby Harrison, went to the area and claimed to have had a sighting too, though it was brief and they obtained no photos or videos. More searches were organized. I think it was during one of these that a searcher, David Luneau, who had a running video camera attached to his boat while he piloted, found out well after the fact that he had recorded a distant woodpecker flying off. He never saw the bird himself and indeed someone watching the video will almost certainly miss the bird even while looking for it—its presence is that distant and brief. And yet this extremely poor video of … a bird, which became infamous, was considered strong evidence by “believers” of the ivorybill’s continued existence, because it seemed to show a lot of white. No definitive sightings, photos, videos or recordings were produced from Arkansas either, but there was the paper by Fitzpatrick et al claiming the woodpecker’s continued existence. There was soon pushback, notably by bird artist and field-guide writer David Sibley, who remarked that the area in question was really quite small and, if I recall correctly, that unlike many birds who could frequent an area without leaving a trace, ivorybills leave huge oblong holes in trees. There didn’t seem to be a lot of those …

    Then there was word that other searchers had found ivorybills in Florida a few years later. One of them was the very Geoffrey Hill whose tweet appears in this post. Louisiana, Arkansas, Florida—they’re all over the place. And yet not one clear incontrovertible photo or video.

    I’d really like to believe that the ivorybill is still out there. But I’m very very skeptical. These are big noisy woodpeckers. They do live in somewhat inaccessible habitat but I don’t think they would be that hard to find with targeted searches. If they were really still out there. The photos and evidence provided are always tenuous with each “rediscovery”.

    By the way, I think the Cuban ivorybill, which may have been a separate species, survived till at least the late 80s, although I’m not sure that the sightings from that time are absolutely bullet-proof. Sadly, the Cuban bird is almost certainly gone too.

      1. Thank you very much for the link. Reading the article brought back memories. When I was young we had a book that was kind of a compendium of different articles on birds and birding. By far my favourite in the book was George Plimpton’s account of his participation in a Texas Christmas bird count with the same Victor Emmanuel featured in the Imperial article. I found it hilarious and read it over and over. Plimpton is an excellent writer.

        Tim Gallagher also searched for the Imperial Woodpecker much later and wrote about it in his book Imperial Dreams. I gather that habitat loss was a major factor in the Imperial’s demise (as it almost always is in a bird’s extinction) but I wonder whether the world’s largest woodpecker would still be with us if the locals hadn’t hunted it as well.

        1. I’m glad you enjoyed the article. To my surprise, in the decades after reading this article, I ended up living in Austin and got to know Victor and also John Rowlett, one of the other characters in the article. Victor and I and his group of birders searched for the Horned Guan (the bird whose song he played in the fancy restaurant in the article) in Chiapas. It was hard going but some people managed to see it.

          1. I’ve never birded in Mexico, other than, in my youth, hopping a fence in some Arizona canyon that I assumed (perhaps mistakenly) was the border. Anyway, I certainly know of the Horned Guan, which must be high up on many birders’ most wanted. I’m sorry that only some in your party got to see it. I assume that these days there are birding tours available with a reasonable chance of finding the bird (?).

              1. Thanks! Yes I know a little bit about the azure-rumped tanager. Wow! (to quote Victor Emmanuel) what an excellent adventure.

    1. From what I recall of the description of their putative habitat from 20yrs ago, the acreage was vast – IIRC the estimate was that only a few % had been searched. Also, it was largely impenetrable both because of swamps and snakes. Furthermore, visibility really only existed in winter months when leaves were gone.

      Also, the link to the videos appears hot but nothing happens for me.

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