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Post by Melanie on Mar 9, 2014 11:43:08 GMT
Large, introductory, nonmajors biology classes present challenges when trying to encourage class discussion to help reinforce important concepts. Lively in-class discussion involving hundreds of students is more successful when a relevant story told with passion is used to introduce a topic. In my courses, each semester begins with thorough treatment of the scientific method, followed by the multiple Darwinian theories of evolution. To reinforce these two important themes, the story of the ivory-billed woodpeckers ecology, evolution, conservation, and probable extirpation has been effective in provoking class dialogue and reinforcing the two themes. Although I describe this approach as a large-class activity, it works well in courses of all sizes. In this article, I discuss teaching with storytelling and detail the use of the ivory-billed woodpecker story as a teaching tool. Scientific Method & Evolutionary Theory Elucidated by the Ivory-billed Woodpecker Story full access James J. Krupa dx.doi.org/10.1525/abt.2014.76.3.3 |
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Post by Melanie on Sept 5, 2014 21:53:07 GMT
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Post by Melanie on Jan 14, 2015 21:43:38 GMT
In 2010 and 2012, five teams of researchers published studies in which they concluded either that the Ivory-billed Woodpecker was extinct or that the odds of finding a living Ivory-bill were less than 1 in 15,625. By what procedure is a species formally declared extinct? How long must we wait before we know it is no more? According to the Committee on the Status of Endangered Wildlife in Canada (COSEWIC Assessment Process, Categories and Guidelines), a species may be judged extinct or extirpated if one of three conditions is met: If there exists no remaining habitat and there have been no records of the species despite recent surveys If 50 years have passed since the last credible record of the species, despite surveys in the interim Or if there is sufficient information to document that no individuals of the species remain alive. Certainty is harder to come by in the United States and in the eyes of the International Union for Conservation of Nature, publisher of the widely accepted IUCN Red List of Threatened Species. According to the IUCN, a species may be called extinct when “no reasonable doubt” remains that the last individual has died: “A taxon is presumed Extinct when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the taxon’s life cycle and life form.” (2001 Categories & Criteria, version 3.1) In the United States, where the Fish and Wildlife Service is required to survey the status of each animal listed under the Endangered Species Act at least once every five years, the official guidance is even vaguer: “Unless all individuals of the listed species had been previously identified and located, and were later found to be extirpated from their previous range,” write federal regulators, “a sufficient period of time must be allowed before delisting to indicate clearly that the species is extinct.” (50 CFR 424.11 – Factors for listing, delisting, or reclassifying species) The last universally accepted sighting of the Ivory-billed Woodpecker was by artist Donald Eckelberry in northeastern Louisiana in April 1944. A version of this article accompanied a 10-page special report on the Ivory-billed Woodpecker written by Jerome A. Jackson. The report appeared in the February 2015 issue of BirdWatching. www.birdwatchingdaily.com/blog/2015/01/09/the-ivory-bill-after-a-decade-just-how-do-we-know-when-a-species-is-extinct/ |
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Post by Melanie on Dec 6, 2015 22:43:03 GMT
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Post by koeiyabe on Dec 12, 2015 14:46:04 GMT
 "The Earth Extinct Fauna (in Japanese)" by Tadaaki Imaizumi (1986) |
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Post by Melanie on Dec 15, 2015 18:01:33 GMT
Tanner and Population Density Posted: December 14, 2015 | Author: markprojectcoyoteibwo | Filed under: Habitat, Ivory-bill History, Old Growth, Uncategorized | Tags: Atchafalaya, Campephilus, density, florida, Herbert Stoddard, Ivory-billed Woodpecker, James T. Tanner, Louisiana, Magellanic Woodpecker, Population, sherburne wma, Singer Tract, wikipedia |Leave a comment I recently gave a talk to the Rockland County Audubon Society, and a member raised what I think is the strongest question about our evidence and about the persistence of the Ivory-billed Woodpecker in general. “How could the species have survived in such low numbers and at such low densities?” In other posts, we’ve pointed to evidence that Tanner missed a population in Mississippi and was somewhat cavalier in his approach to evaluating potential habitat, disregarding advice Herbert Stoddard gave him in 1936, “The area where they (Ivory-billed Woodpeckers) may occur at present is simply tremendous, not restricted as many believe.” A recent study on Magellanic Woodpeckers points to another factor that raises even more doubt about Tanner’s estimated population of 22 in 1939. The study was conducted in an old growth Lenga forest in Patagonia. According to this study: “Our results show that Magellanic Woodpecker family groups require a minimum of 100 ha in old-growth forest habitat; thus, forest patches in less favourable forest conditions (e.g., younger, managed, fragmented, mixed forests) should probably be much larger to support a resident pair or family.” The specific criteria that Tanner used for estimating the 1939 population at approximately 22 are unclear, but he assumed a maximum carrying capacity of six square miles per pair. The Wikipedia entry on the IBWO is even worse and is generally rife with bad information; the editors there expand Tanner’s six square miles to “9.7“. Elsewhere, Tanner suggested a minimum home range of two and a half to three square miles. These numbers are somewhere between six and 16 times the minimum for a large southern congener that, like the ivorybill, lives in more temperate habitat than others in the genus. Thus, there is a strong possibility that Tanner severely underestimated ivorybill populations in Florida. If he was so badly wrong about home range, he’s more likely to have missed populations in areas that he rejected for being suboptimal and not expansive enough. Double the minimum acreage required by the magellanic in optimal habitat and apply that number to the ivorybill, and Sherburne, a large Louisiana WMA, could theoretically be home to just under 90 family groups. (We don’t think this is the case.) Even at 450 hectares per family group, the carrying capacity in Sherburne would be nearly 40. Such numbers are improbable in the extreme, but 9 or 10 family groups in an area that size would be very hard to detect. With significantly smaller home range requirements, a substantially larger population in 1939, and a recognition that Singer Tract-like conditions are not a requirement (as Tanner himself made clear), various survival scenarios become considerably more plausible, assumptions about low densities become more questionable, and the quantity of potential habitat is far greater than anyone has imagined. Edited to add: Although the study referenced above is more recent, Noel Snyder made the same basic argument about magellanics and other congeners in The Travails of Two Woodpeckers (2009). Snyder posits that hunting pressure, not habitat loss, was the primary cause of the ivorybill’s decline. Snyder (who to the best of my knowledge has little hope for the ivorybill) does not fully address how Tanner’s assumptions might have affected his population estimates and habitat evaluations. He also doesn’t consider how taking Tanner at face value has influenced both search protocols and the “credibility” of post-Singer Tract reports. Nevertheless, he does hint at what I suspect is the key to the species’ survival: “With food supplies degraded, not eliminated, a reasonable possibility appears to exist that many ivory-bill populations in logged regions might still have found enough food to persist and might have endured at modest densities, had they been free of shooting pressure. The long persistence of the ivory-bill in one quite thoroughly logged region in Cuba supports this possibility . . .” In my view, Snyder goes a little too far in downplaying specialization as a factor, even if Tanner overplayed it. It’s pretty clear – from range, habitat, and morphology – that ivorybills are more specialized than pileateds. But if the IBWO did persist after World War II and Snyder is right that hunting was a major factor in the species’ decline (even in the Singer Tract), there may be even more room for optimism, since hunting practices changed considerably in the post-war era. projectcoyoteibwo.com/2015/12/14/tanner-and-population-density/ |
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Post by Melanie on Apr 5, 2016 12:17:12 GMT
Awesome Ivory-billed woodpecker video from 1935
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Post by Melanie on Apr 27, 2016 9:59:51 GMT
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Post by surroundx on Sept 18, 2016 13:24:49 GMT
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Post by surroundx on Sept 18, 2016 13:35:33 GMT
"In the opinion of the National Audubon Society, the Ivory-billed Woodpecker may now be extinct. It has been many years since it has had any reliable reports of birds in or near the Singer tract. The birds have not been seen on the Florida sanctuary for these birds since it was established. It was made a sanctuary after two birds were observed there on March 3, 1950, by Whitney H. Eastman. The Society believes that there may still be a few birds in certain areas in Florida but has received no reliable reports of such birds in the past two years." Source: Gabrielson, Ira N., Griscom, Ludlow and Lloyd, Hoyes. (1954). Report of the American Ornithologists' Union Advisory Committee on Bird Protection. Auk 71(2): 186-190. |
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Post by surroundx on Sept 18, 2016 13:42:50 GMT
"Recently a convincing, and probably accurate, but still unconfirmed report of a pair of Ivory-billed Woodpeckers in East Texas has been received. It seems advisable to determine the accuracy of this before reporting details" [p. 247-248] Source: Munro, David A., Pough, Richard H., Hochbaum, H. Albert, McCabe, Robert A., Gabrielson, Ira N. and Cottam, Clarence. (1961). Report to the American Ornithologists' Union by the Committee on Bird Protection, 1960. Auk 78(2): 244-255. |
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Post by surroundx on Nov 15, 2016 13:18:04 GMT
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Post by surroundx on Nov 15, 2016 13:20:54 GMT
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Post by Sebbe on Jan 25, 2017 16:00:00 GMT
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Post by Melanie on Jan 25, 2017 22:03:26 GMT
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Post by surroundx on Jan 26, 2017 0:37:06 GMT
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Post by Melanie on Jan 27, 2017 9:46:54 GMT
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Post by Melanie on Feb 19, 2017 23:07:05 GMT
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Post by surroundx on Apr 22, 2017 2:41:10 GMT
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Post by Melanie on Oct 2, 2017 10:07:31 GMT
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