Ivory-Billed Woodpecker continued (1 Viewer)

[dantheman]

Before I try to answer your questions, let's discuss this ebird info. It sure does look like a LOT of birding going on, doesn't it? I mean all those huge blue icons, some with fire symbols suggesting loads of pileated sightings. Wow.

Now let's consider one period of time, 2019, the last full year before Covid. Going through each entry, looking at the number of birds reported, and taking into account that there were some groups of people birding together and likely reporting the same birds, I give a ballpark estimate of 100 pileated woodpeckers spotted and reported during fewer than 100 man-visits in the habitat during 2019. Is that really a lot for approximately 500,000 square kilometers? Let's see...

Studies suggest (if memory serves) that there are approximately six pairs of pileated per square mile, which is about 2.6 square kilometers, to be found in good habitat. By my calculations, there should be about 2,307,692 pileated at the Pearl River. During 2019, approximately 100 were documented, or about 0.005% of the number of pileated that could potentially be found. In other words, 1 out of every 2000 pileated were seen and documented during 2019.

I may have failed to carry the one or something. Please do correct me if the math or logic is wrong.

The area of habitat concerned looks to me more like c400 square kilometres or so, via eg googlemaps? (5km x80km). However the portions in the maps in Zanders posts above are only a portion of that, so taking eg 100km - On that basis, and roughly on the figures you give of 100 visits and 2 pairs per square kilometre, that would give 200 pairs (400 birds) or 1 in 4 Pileateds recorded in a year?

(Edit: I have a funny feeling the 500,000 km2 may refer to the entire catchment area of the Pearl River, China ... ?)

 

[Deb Burhinus]

Why do people who have witnessed something need to scientifically prove to themselves that it happened?

You misunderstood my post.

Of course you don’t need to ‘prove to yourself’ you saw a IB. But, your belief that what you saw was actually an IBWO can not be proven to me without some form of extrinsic evidence directly relating to that experience that convinces me beyond all reasonable doubt that you did indeed see an IB and therefore the IB is extant.

’Belief’ is not proof.

Which goes back to why I respond to your assertion that ‘conclusiveness is in the eye of the beholder’ by saying it belongs in the paradigm of belief systems not scientific and statistical analysis. This is why I say to you, in the context of Searcher v Sceptic debate revolving around the Searchers‘ provable hypothesis that IB is extant, so ‘prove to me that it was actually an IB that you believe you saw’! This is what it boils down to. Everything else is nongermane to the thesis.

 

[bottomlands]

You misunderstood my post.

Of course you don’t need to ‘prove to yourself’ you saw a IB. But, your belief that what you saw was actually an IBWO can not be proven to me without some form of extrinsic evidence directly relating to that experience that convinces me beyond all reasonable doubt that you did indeed see an IB and therefore the IB is extant.

Where have I said or implied that you should believe my sightings and ID were correct? I thought I had made it very clear I understand that sightings are not admissible evidence for IB persistence. Skeptics will not accept them. So let me restate: My sightings are the basis for my belief. Period. End of claim.

 

[bottomlands]

The area of habitat concerned looks to me more like c400 square kilometres or so, via eg googlemaps? (5km x80km). However the portions in the maps in Zanders posts above are only a portion of that, so taking eg 100km - On that basis, and roughly on the figures you give of 100 visits and 2 pairs per square kilometre, that would give 200 pairs (400 birds) or 1 in 4 Pileateds recorded in a year?

(Edit: I have a funny feeling the 500,000 km2 may refer to the entire catchment area of the Pearl River, China ... ?)

Yeah, good catch. My analysis of eBird reports were for about 50 linear miles of the river, a much larger area than what Zanderll showed in his picture. And I must have screwed up the math a lot. Now I'm getting about 4% seen and documented. Someone else can redo an analysis of whatever size and time period they like, and I expect the overall conclusion will be similar. Only a very tiny percentage of pileated are reported and most go unseen.

 

[etudiant]

There are several Campephilus species fairly abundant in the southern half of Latin America which could easily be transplanted to the southern US.
With luck, they would refill the niche that the Ivory Bill left vacant.
What prevents this from getting done?

 

[1TruthSeeker]

How would you find one bird?

How long would it take?

How long would it take you to get an equivocal picture/vid and how ?

How long would it take you to get an unequivocal picture/vid and how ?

Your recon says this about Campephilus isla which found only here:

Above is a large island the exact size of Great Britain (see map and key) called South Great Britain discovered by the great Englishman naturalist Catesby. It has ~ 7.5 million acres of forest (see pink) surrounded by farmland, small towns and a few small cities. The island is a perfect size correlate to GB but everything else is like Louisiana or N FL, USA. The island is situated 50 miles off the USA from FL to SC (subtropical to temperate zone). There coincidently are 7.5 million acres of forest in the mainland IB Woodpecker habitat,

The human population is one/seventh of the present UK, and is like Louisiana at 90 people/ sq mile but half of them are in 5 small cites, meaning large areas around the forests have only 2 people/sq mile (farms with small patches of forest, few birders). Note for comparison the pop of UK is ~ 660 p/ sq mile.

Half the 7.5 million forest acres are private land, and you should not enter but certainly some minimal trespassing on only the edges occurs. Trespassing any further in will risk arrest or worse and it's difficult anyway since the few gated roads are locked and boat ramps are not open to you and a boat and your parked vehicle will be noticed on the dead end road/ramp area.

The pinkish areas are forests, the blue lines through the forests are large rivers and rivers, some a hundred + miles long, .05 to 1 mile wide. Streams, creeks, sloughs and oxbow lakes number in the thousands and are not visible due to scale. The thin pink forests are .25 to 2 miles wide and C. isla can use them. Line transects are mostly impossible.

There are paved roads almost completely ringing or bordering every forest, two hundred yards from the forest edge, through farm fields and 400 small towns. There are only 3 paved roads cross the lesser width of each large forested area. There are mud and dirt roads every 2 miles, most private, IN seasonal UPLANDS, but there are many 50 sq mile areas with no roads since they are seasonally flooded. The thin strips of forests on the map are along rivers and there is bridge every 20 miles. The outer areas/perimeters of the large forested areas are mainly planted pines for silviculture average height 70 ft and dbh 18 in. The many lower topo areas through the pine forest have nice second growth to late successional riparian forest with cypress, water hickory ,various oaks, maples, willows, tulip, dogwood, sweet gums etc., often some late successional patches of 100 acres. A hundred patches of 1000 acres to several 30,000 contiguous flooded acres of cypress are spaced along the rivers, where the river slope is minimal.

The center of the forest areas are seasonally flooded or flooded and totaling 1,000,000 acres of late successional riparian forest with 90 -130 foot canopy. Of this maybe 70,000 acres is virgin with 130 ft canopy .

Best time to search is fall to early spring when snakes, gators, ticks, spiders, boars, heat and humidity can be tolerable. Spring though summer can be very difficult and unproductive. Best technique it to camp because it can take a half day to 1 day to get to best areas. Otherwise you need to get up at 3AM every day and hike/paddle in for 4 hours in and 4 out every day. Note there are no bars, convenience stores, photo stores, hospitals, showers, in the forest......just forest, forest, creek, swamp, forest, bayou, river, logs, etc. There is no place to charge your cam. batteries and cell phone coverage can be e spotty to non-existent in best IB isla areas.

In those forests are perhaps 20 ? C. isla left in 3, 4, large pockets and they do not like people and are relatively smart and quiet. No attraction method has worked but sometimes they DK or kent when you are near. They are behaviorally and morphological just like C principalis. They also suffered heavy hunting pressure just when the population was dropping. D. pileatus is uncommon to common in the forests. On average you will get 150 a week and get pictures of 1 to 4 if you try, which you should not be doing since its not the target.

How would you find one bird?

How long would it take ?

How long would it take you to get an equivocal picture/vid and how ?

How long would it take you to get an unequivocal picture/vid and how ?

pictures may be posted

 

[Deb Burhinus]

Around 99% of all pileated went unreported.

You lost me a bit with the maths and language but are you saying:

‘all unreported Pileated were unseen by any observers ie all observers who saw Pileated uploaded their sightings to ebird

or are you saying

‘not all observers reported their Pileated sightings to ebird ’

Within the 99% how can you know the difference and therefore draw a conclusion from that, IBs are evading observation too?

 

[bottomlands]

You lost me a bit with the maths and language but are you saying:

‘all unreported Pileated were unseen by any observers ie all observers who saw Pileated uploaded their sightings to ebird

or are you saying

‘not all observers reported their Pileated sightings to ebird ’

Within the 99% how can you know the difference and therefore draw a conclusion from that, IBs are evading observation too?

I'm now estimating that 96% of pileated in the Pearl River bottoms are not reported on eBird. If there is only one pair of IB in that region, what are the chances that birders would see and photograph them? I think nil. (I'm using one pair, because that is what Zanderll and I are discussing - whether one pair of IB could go unphotographed.)

 

[Deb Burhinus]

tate: My sightings are the basis for my belief. Period. End of claim.

But then have I misunderstood you all along - I thought you have been here claiming that the IB is extant?

I see now that you have no evidence (or at least any you wish to reveal to us), to support such a claim in fact. That, as you say, it is just a personal belief to which you are perfectly entitled and not anyone’s else’s business. Apologies.

I'm now estimating that 96% of pileated in the Pearl River bottoms are not reported on eBird. If there are only one pair of IB in that region, what are the chances that birders would see and photograph them

I guess that calculation (using your 96% baseline for unreported Pileated) would depend on what percentage of birders who saw a portion/most? of the 96% but didn’t upload those sightings to ebird. Until that quantity is known, I am a bit puzzled how one can infer that a pair of extant IB would not therefore be found in the Pearl River bottoms either.

 

[bottomlands]

But then have I misunderstood you all along - I thought you have been here claiming that the IB is extant?

No, I'm not that guy. I'm the other guy - the one trying to figure out why Zanderll and some of the others are 100% certain that IB are extinct.

Go to sleep, Deb. It's very late.

 

[Deb Burhinus]

Go to sleep, Deb. It's very late

Actually, I’m working, it’s the quietest time of the ‘day’! 🙂

... then I shall do some reading on statistical probabilities, the theory of ‘null hypothesis‘ and how ’extinction’ might apply here - then finally I will try to find a way of proving a negative because until I do, I am certain no one can claim to be 100% certain that the IB is extinct only that the starting presumption is that it must be so 🙂

But then have I misunderstood you all along - I thought you have been here claiming that the IB is extant?

No I am not that guy

My sightings are the basis for my belief.

Bismarck Honeyeater said:
So, having previously said that you want to answer this, what evidence would (has?) convinced YOU that IBWO still exists.
Presumably some of the private evidence, please let us know.

Primarily my own sightings, and sightings by others, plus some other evidence you would not think conclusive.

Claims to have had IBWO sightings ipso facto IBWO is extant

 

[etudiant]

The record of accidentals indicates that birds are prone to major shifts away from their normal habitat.
Sadly, we've not had any errant Ivory Bills showing up in NYC Central Park, although we did have a Townsend Warbler just across the Hudson.
Still, that there has been no report of such an excursion in the past 75 years is surely a relevant factor.

 

[bottomlands]

Is it possible - yes they could evade detection assuming they always kept to areas that no-one ever visits, But is that a valid assumption?

Given my estimate above (feel free to do you own calucations), 96% of pileated are not seen and reported on eBird each year. That suggests the area is not well birded enough to make IBWO sightings and photography likely.

The problem is where did that pair come from?

Could have been born there, could have come there when dispersing from elsewhere. Why does it matter?

Why weren't they unreported there before?

See above. One pair of birds in lots and lots of habitat. Relatively few birders.

Just the one pair?

That is what we're discussing, because that is enough for them to be extant.

Do they breed?

Maybe, maybe not. Maybe they are the last pair. Does it matter to the question of whether they are likely to be photographed?

If so where do they offspring disperse to?

Elsewhere. Or maybe there is no offspring.

A pair can't have persisted on their own for 50 years so what about other birds elsewhere? Why does no-one see them well enough to prove their existence?

As I've mentioned people do see them. You and others just dismiss the sightings.

Look, I don't have all the answers. The birds could be increasing in numbers, or maintaining numbers. They may be circling the extinction bowl and are about to get flushed due to fragmentation of habitat into disconnected sections and the effects of inbreeding. There may be no birds at the Pearl, 2 birds at the Pearl, or 20 birds at the Pearl. All I'm saying is your claim that there is "no way" the birds are extant, and zero chance a pair of IB could be persisting at the Pearl today seems poorly considered.

I'd love to hear you explain more about why you are so certain they are extinct, if you're willing. Because I just don't understand how you can have such an absolute stance on the question.

A couple questions for you:

1) Skeptics are said to believe that when a birder thinks they he has seen an IB and reports it, he has probably mis-ID'ed a pileated. Do you believe that is true? If so, why?

2) What do you think would happen if an average birder who is not searching for IB sees what he thinks is probably IB. Is that birder more likely to (A) report an IB on eBird, (B) report a pileated to be safe and avoid being ridiculed, or (C) leave the bird off his report?

 

[1TruthSeeker]

 

[1TruthSeeker]

 

[Farnboro John]

View attachment 1367251
How would you find one bird?

How long would it take?

How long would it take you to get an equivocal picture/vid and how ?

How long would it take you to get an unequivocal picture/vid and how ?

Your recon says this about Campephilus isla which found only here:

Above is a large island the exact size of Great Britain (see map and key) called South Great Britain discovered by the great Englishman naturalist Catesby. It has ~ 7.5 million acres of forest (see pink) surrounded by farmland, small towns and a few small cities. The island is a perfect size correlate to GB but everything else is like Louisiana or N FL, USA. The island is situated 50 miles off the USA from FL to SC (subtropical to temperate zone). There coincidently are 7.5 million acres of forest in the mainland IB Woodpecker habitat,

The human population is one/seventh of the present UK, and is like Louisiana at 90 people/ sq mile but half of them are in 5 small cites, meaning large areas around the forests have only 2 people/sq mile (farms with small patches of forest, few birders). Note for comparison the pop of UK is ~ 660 p/ sq mile.

Half the 7.5 million forest acres are private land, and you should not enter but certainly some minimal trespassing on only the edges occurs. Trespassing any further in will risk arrest or worse and it's difficult anyway since the few gated roads are locked and boat ramps are not open to you and a boat and your parked vehicle will be noticed on the dead end road/ramp area.

The pinkish areas are forests, the blue lines through the forests are large rivers and rivers, some a hundred + miles long, .05 to 1 mile wide. Streams, creeks, sloughs and oxbow lakes number in the thousands and are not visible due to scale. The thin pink forests are .25 to 2 miles wide and C. isla can use them. Line transects are mostly impossible.

There are paved roads almost completely ringing or bordering every forest, two hundred yards from the forest edge, through farm fields and 400 small towns. There are only 3 paved roads cross the lesser width of each large forested area. There are mud and dirt roads every 2 miles, most private, IN seasonal UPLANDS, but there are many 50 sq mile areas with no roads since they are seasonally flooded. The thin strips of forests on the map are along rivers and there is bridge every 20 miles. The outer areas/perimeters of the large forested areas are mainly planted pines for silviculture average height 70 ft and dbh 18 in. The many lower topo areas through the pine forest have nice second growth to late successional riparian forest with cypress, water hickory ,various oaks, maples, willows, tulip, dogwood, sweet gums etc., often some late successional patches of 100 acres. A hundred patches of 1000 acres to several 30,000 contiguous flooded acres of cypress are spaced along the rivers, where the river slope is minimal.

The center of the forest areas are seasonally flooded or flooded and totaling 1,000,000 acres of late successional riparian forest with 90 -130 foot canopy. Of this maybe 70,000 acres is virgin with 130 ft canopy .

Best time to search is fall to early spring when snakes, gators, ticks, spiders, boars, heat and humidity can be tolerable. Spring though summer can be very difficult and unproductive. Best technique it to camp because it can take a half day to 1 day to get to best areas. Otherwise you need to get up at 3AM every day and hike/paddle in for 4 hours in and 4 out every day. Note there are no bars, convenience stores, photo stores, hospitals, showers, in the forest......just forest, forest, creek, swamp, forest, bayou, river, logs, etc. There is no place to charge your cam. batteries and cell phone coverage can be e spotty to non-existent in best IB isla areas.

In those forests are perhaps 20 ? C. isla left in 3, 4, large pockets and they do not like people and are relatively smart and quiet. No attraction method has worked but sometimes they DK or kent when you are near. They are behaviorally and morphological just like C principalis. They also suffered heavy hunting pressure just when the population was dropping. D. pileatus is uncommon to common in the forests. On average you will get 150 a week and get pictures of 1 to 4 if you try, which you should not be doing since its not the target.

How would you find one bird?

How long would it take ?

How long would it take you to get an equivocal picture/vid and how ?

How long would it take you to get an unequivocal picture/vid and how ?

pictures may be postedView attachment 1367252

I can see at least one false premise in the above:

"Best time to search is fall to early spring when snakes, gators, ticks, spiders, boars, heat and humidity can be tolerable. Spring though summer can be very difficult and unproductive."

Woodpeckers in autumn and winter are not easy to locate as they are silent and concentrate on feeding and saving energy. The very best time to search for woodpeckers is when they are displaying, but a very close second comes when they are nesting, because then they are tied inescapably to a particular area, have to make lots of conspicuous flights and also interact extensively by calling and continuing to declare territory. As the juveniles emerge from the nest and take their first naive flights and interactions with the outside world they also become as conspicuous as they are ever going to be, especially as they continue to call to adults to food-beg etc. (Not to mention that at this time the population is as high as it gets through the year.)

Prioritising observer comfort over search favourability is a schoolboy mistake.

John

 

[dantheman]

View attachment 1367251

Leaving aside everything else, I thought you were going to be posting a picture of Scotland wearing a Tam O'Shanter there initially ... ;-) Mis-id or what!

It's all an interesting subject ... but also all fairly subjective. There are any number of assumptions, correlations, factors - but a great basis for some (fairly shaky but fun?)mind exercises. We can all discuss till the cows come home - could a population of crow sized, distinctive arboreal birds evade detection for 70 years in the above scenario - methinks not (partly because the areas are too wide?). Ripe for computer simulation imo, using simulated data for eg ebird amongst other things. Another parallel - how about comparing ebird and data for species in inaccessible swamp/wet forest in the rainforest S America for rare species (ie desirable for world listers)?

 

[ZanderII]

How would you find one bird?

How long would it take?

How long would it take you to get an equivocal picture/vid and how ?

How long would it take you to get an unequivocal picture/vid and how ?

Your recon says this about Campephilus isla which found only here:

Above is a large island the exact size of Great Britain (see map and key) called South Great Britain discovered by the great Englishman naturalist Catesby. It has ~ 7.5 million acres of forest (see pink) surrounded by farmland, small towns and a few small cities. The island is a perfect size correlate to GB but everything else is like Louisiana or N FL, USA. The island is situated 50 miles off the USA from FL to SC (subtropical to temperate zone). There coincidently are 7.5 million acres of forest in the mainland IB Woodpecker habitat,

Nice analogy, thanks for going to considerable time to construct it; it doesn't work though.

Appended below is the United Kingdom which fits with plenty of room into the Peruvian Amazon and several times over into the 6 million square kilometers of the Amazon basin, Much of it is still a vast untouched wilderness and it is even home to uncontacted people.

Only one species of woodpecker (Snethlage, E, 1912 Varzea Piculet) has been described from this vast wilderness since the end of the 19th century. In fact of the 236 species of woodpecker recognised by IOC only 8 others have been described after 1899: Snethlage, E, 1924 Ochraceous Piculet, Stager, 1968 Fine-barred Piculet, (Bates, GL & Kinnear, 1935) Arabian Woodpecker, Oberholser, 1919 Little Grey Woodpecker, Reichenow, 1901 Stierling's Woodpecker,
Todd, 1919 Choco Woodpecker, (Rothschild, 1901) Lita Woodpecker and Olson, 2013 Bermuda Flicker.

Note the last was described from subfossil remains.

We described the lion's share of woodpecker diversity in the 18th century. Why? Because woodpeckers are easy to find and document, which in these cases meant shooting them to obtain a type specimen. It is considerably easier to take a photograph with a DSLR than collect a woodpecker with 19th century weapons. The thesis of Mike Collins and others is that there are perhaps 100s of IBWO distributed in the southern USA across multiple states and that despite huge efforts to look for them they can't be adequately documented.

There is still some nominal wilderness left in the southern USA but it is not big enough to hide a population of massive woodpeckers for 70 years, any more than it could hide a population of undescribed hominids. Woodpeckers aren't like a set of keys, yes we could envisage a single woodpecker hiding in the Pearl, but what you and Bottomlands seem to fail to grasp is that a single woodpecker can't exist in splendid isolation, even if it did we would still expect it to be seen by people if it is looked for. Unlike keys they move around, make lots of noise and are generally obvious, like most woodpeckers.



In case you were wondering these are the description dates for Campephilus:

(Bonaparte, 1845) Powerful Woodpecker

(Tschudi, 1844) Crimson-bellied Woodpecker

(Boddaert, 1783) Red-necked Woodpecker

(Lichtenstein, MHK, 1818) Robust Woodpecker

(Gmelin, JF, 1788) Crimson-crested Woodpecker

(Hartlaub, 1844) Pale-billed Woodpecker

(Lesson, R, 1845) Guayaquil Woodpecker

(Valenciennes, 1826) Cream-backed Woodpecker

(King, PP, 1827) Magellanic Woodpecker

(Linnaeus, 1758) Ivory-billed Woodpecker

(Gould, 1832) Imperial Woodpecker

 

[KenM]

View attachment 1367261View attachment 1367261

Awesome pics.Truthseeker!
In acreage terms, roughly...how much (%) of the purported 8 million acres of bottomlands would your images represent, just a crude approximate if possible?

Many Thanks

 

[Hauksen]

Hi,

The cognitive dissonance in that paper is mind-bending (Collins 2019)

What do you think of the E = A/B * sigma formula? In my opinon, it's not applicable to a situation where the target species is (by Mike's own admittance) highly mobile (and more mobile than the searcher). It apparently doesn't even reflect his actual search approach, either.

I would say that the probability of a target species sighting is the probability that the species is in the vicinity of the searcher during any given period of time, multiplied by the probability that the searcher spots the target species in a time period equivalent to that in-vicinity period.

Thus, targeting a highly mobile species actually increases the chances of detection, rather than decreasing it as Mike suggests.

The best strategy for that situation obviously is to maximize the probability of spotting the target, which can be achieved by staying at the location that offers the best view. Which, as Mike explains in his article, is just what he did for on the day of his (claimed) sighting.

Regards,

Henning