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The first paragraph at the above link contains this claim by Phillip Hoose (the bold font is mine):
They mated for life, roamed the forest in pairs, and could live to be as old as thirty.What is the basis for that longevity claim? Note that The Birds of North America account for the Ivory-bill lists "no data" for the Ivory-bill lifespan.
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I know this doesn't belong here, but I couldn't resist:
From Fishcrow's website:
10-21-06. I intended this to be my last day in the Pearl until later in the season, but then I saw an ivorybill about three miles south of the area where Susan and I heard loud raps a few weeks ago. I saw the bird for a few seconds as it landed high in a tree with its back to me. With the sun coming from behind me, it was spectacular to see the bird flutter its outstretched wings to make adjustments for the landing. Although this species is extremely wary, the brilliant white secondaries are obviously meant to be seen.
10-22-06. Susan and I briefly visited the location of the sighting before I loaded up the car and hit the road. I really need to get back to Virginia, but I decided to stay on I-10 and head to the Choctawhatchee for a brief visit rather than making the usual turn onto I-65. I arrived late in the afternoon and ran into Geoff Hill and several others.
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So I get a fantastic look at a perched Ivory-bill, and then next day I pack up and LEAVE???
What a nutball!
So I get a fantastic look at a perched Ivory-bill, and then next day I pack up and LEAVE???
Coming down from a mushroom trip can be a bummer sometimes.
That must put the crow up to, what, 15 or 20 encounters? Bobby needs to do some catching up!
Tom wrote:
".....Note that The Birds of North America account for the Ivory-bill lists "no data" for the Ivory-bill lifespan."
C'mon Tom, it's now well-established that "Jackson is incorrect" and doesn't really know anything about IBWOs....
OK! OK, already! I'm back to the practical joke theory.
"They mated for life"
Yes the guess at 30 years is bad but so is the speculation on mate fidelity. Okay so assume for the sake of argument that this means annual mate fidelity of 100 percent. As most of you know this would be a very uncommon strategy. Pairs that fail have lower annual mate fidelity so this would mean that IBWO pairs that fail would not buy into that but would stay with the mate with which they failed.
But even if we think that mate fidelity is 100 percent there has to be some mortality that prevents a bird from breeding with last year's mate. If annual survival is say 95 percent then five percent of the birds have to find new mates every spring. If the birds live to be 30 years old and have a 5 percent chance of losing a mate in any given year then few birds are going to get through their 30 years breeding with the same mate.
I think that portraying them as long-lived and having life-long pair bonds makes them more attractive to the public and especially to the donor demographic (who are both feeling their age and by now know that life-long mate fidelity is not as easy as it seemed to be when they were putting that into their vows). Hoose and crew know all about how to make things attractive to those who may contribute money. Try selling clothing or peddling a credit card that shows a short-lived, highly promiscuous species that practices cannibalism.
Look up the BNA accounts for other woodpecker species. What is longevity for woodpeckers in general?
Fishcrow sees Ivory-billed!
p>0.95
Later...
"Fishcrow sees Ivory-billed!
p>0.95
Later..."
Fishcrow takes blurry video!
P>0.99
Now.....
BNA accounts list 10-15 years as maximum lifespan for most woodpecker species, though data are considered weak and outdated for most species. A modern analysis is needed.
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