A Façade of Science: An analysis of the Jack Ward Thomas report, based on sworn testimony of members of the Thomas Committee. A report for the Association of O & C Counties & the Northwest Forest Resource Council.

(Note: The reading of this report is tedious. Please endure it; if you want to know the truth, this is your opportunity. The Forest Service and the U.S. Department of Fish & Wildlife, at all levels of decision making about the policy of our forest management in regard to the spotted owls, have quoted the Thomas report. After the release of this report, which we print with the permission of Northwest Forest Resource Council, (all such agencies) should become null and void.)

August 1990

By Preston, Thorgrimson, Shindler, Gates and Ellis


In May of 1991 the Interagency Scientific Committee to Address the Conservation of the Northern Spotted Owl (commonly called the "Thomas Committee" or "ISC") issued its report recommending a conservation strategy to maintain a viable population of spotted owls in Washington, Oregon and California. The report recommended that seven million acres of federal land in the three states be set aside as habitat conservation areas (HCA's) for spotted owls, most of which are to be large enough to provide habitat for at least 20 pairs of owls and are to be no more than 12 miles apart from each other. No timber harvesting is permitted within the HCAs. Intervening federal timber lands are to be managed under a "50-11-40" rule in which 50% of each quarter township of federal land must at all times contain trees averaging 11 inches in diameter at breast height and 40% canopy closure.
Between February and May, 1991 five of the six members of the ISC gave sworn testimony in the spotted owl lawsuit known as Portland Audubon Society v. Lujuan (The head of the Agricultural Department at that time) and Seattle Audubon Society v. Robertson (the US Forest Service Chief at the time). Committee members Jack Ward Thomas, Jared Verner, Eric Forsman, Barry Noon and Joseph Lint each testified under oath in depositions and Portland Audubon v. Lujuan. Drs. Thomas, Verner, Forsman and Noon also testified under oath in depositions in Seattle Audubon v. Robertson. Dr. Thomas, Verner and Forsman testified in person before Judge Dwyer in Seattle Audubon Society v. Robertson.
The sworn testimony of these scientists reveals that the ISC Strategy is primarily the product of subjective personal judgment of the members of the Committee rather than an objective scientific product based on verifiable facts, reliable data or recognizable scientific theory.
In large measure the ISC Report presents a facade of science to create the appearance that the ISC Strategy is firmly grounded in objective, verifiable science when in fact it is not. Every component of the ISC Strategy is primarily the product of the "professional judgment" of the members of the Committee. This judgment is untested, unexplained and represents, in the words of one committee member, a "management exercise" rather than a scientific effort.

This does not mean that the ISC Strategy is necessarily wrong or fatally flawed. It means simply that the aura of an objective science which has been cast over the ISC Report in not justified, and should not inhibit close scrutiny of every component of the ISC Strategy by policymakers, administrative officials and legislators who must make the ultimate legal decision as to whether the ISC Strategy should be adopted and implemented by the Forest Service, the Bureau of Land Management, or the Fish and Wildlife Service.


The ISC did not keep any minutes, notes or other documentation of its discussion in the period of October 1989 - March 1990 during which it prepared its conservation strategy. (Noon, p. 64) Thus, it is impossible to recreate the actual analytical process, which led to the ISC Strategy. Further, the Committee did not retain the raw data, which it analyzed in developing the strategy. Rather, each Committee member that supplied data simply retained that data in his own office. (Noon p. 29) The Committee members made no effort to verify whether each other's data was correct, but simply accepted it as true. (Noon p. 25) However, when Dr. Forsman, who supplied large quantities of data to the Committee was asked in his deposition to verify his own calculations, which were used by the Committee, he was unable to do so. (Forsman p. 13, p. 213) He explained that he would have to return to his lab to attempt to verify the data, and even then was not sure he would be able to do so. (Forsman p. 14, p. 109)
In the absence of documentation of the ISC deliberations, the only available source of information is the recollections of the Committee members describing the process followed by the Committee. The ISC members who testified uniformly identified four sources of information which were relied on in the development of the strategy empirical data, scientific theory, computer models and professional judgment. (Verner p. 45, Thomas p. 97, Noon p. 57) All four sources were equally important to the Committee. (Verner p. 46)
The Committee did not look to any of these sources of information to prove the validity of a particular conservation strategy. Rather, it viewed its proposed conservation strategy as a hypothesis, and it used each of the four sources of information to attempt to disprove the conservation strategy would succeed. (Thomas p. 97, Verner p. 97) This approach reflects the common scientific view that scientists can never prove anything; they can simply disprove on hypothesis by showing that it is contradicted by existing fact. (Thomas p. 202)
This approach had enormous impact on the process followed by the Committee. The Committee acknowledged that there is virtually no statistically reliable, relevant, demographic data on any of the vital behaviors of the spotted owl (birthrates, reproduction rates, longevity, mortality rates). (Verner p. 179) This lack of data should have made it difficult for the Committee to come up with a reliable plan. However, by using the empirical data merely to attempt to disprove the validity of its hypothesis, the Committee minimized the absence of data by finding that the lack of data simply failed to disprove its hypothesized conservation strategy.
The importance of this process is that the Committee could have developed a much different conservation strategy and the empirical data would equally have failed to disprove the validity of that strategy. It could have proposed considerably smaller HCAs considerably farther apart and the empirical data would no more have disproved the validity of that approach than of the approach ultimately recommended by the ISC. The absence of reliable data became significant to the Committee, although it should have been central to recognizing the limits of the Committee's ability to develop a valid spotted owl plan.
Likewise, the absence of recognized scientific theory (a "theory is a hypothesis which has been sufficiently tested and validated over time to become generally recognized as true) also should have inhibited the ISC from developing long-term conservation plans. Instead, the absence of relevant scientific theory merely failed to disprove the particular conservation strategy the Committee developed.
Equally, the highly questionable nature of the population simulation models developed by the Committee should have been a further reason for it to hesitate to develop a long-term conservation plan, but instead the weakness of the models merely resulted in failing to disprove the proposal developed by the Committee.


A. Size of HCAs. The single most important component of the ISC Strategy is the requirement for the creation of so-called "Category 1 HCAs" large enough to hold at least 20 pairs of spotted owls. The vast majority of the seven million acres of federal land included within protected areas under the ISC Strategy is within Category 1 HCAs. No valid empirical data.
The Committee "had no studies of owls" to indicate how large each HCA should be in a system composed of many HCAs in order to minimize the risk that every HCA will lose its owl population and the species will go extinct. (Verner p. 179)
Lacking such direct empirical data, the ISC instead looked at studies of other large-bodied birds like ravens (The spotted owl is considered a large-bodied bird). (Verner p. 66-67) The data relied on by the Committee came from studies of birds living off the coast of England and California. (Verner p. 67). None of the studies were of birds living in forests like those of the Northwest.
The Committee judged the English island studies to be more relevant to the forests of the Northwest. (ISC Report at 289)
These English studies revealed that no population of birds larger than 11 pairs in size had ever gone extinct in any of the studies, which had lasted as long as 30-40 years. (ISC Report 289) Dr. Noon, the mathematician on the Committee, took the empirical data from these English island studies and turned them into a linear regression model to predict how long populations of different sizes would survive on an island. This model projected that a population of 20 pairs of birds would live on an island for 50 years. Report at 289. Table 0-3; (Verner p. 82-83)
The Committee relied primarily on this 50-year linear regression projection for a population of 20 pairs on an island to justify the 20-pair HCA size specified in the ISC Strategy. (Verner p. 83-84) However, the Committee's anticipation was that if an individual cluster went extinct (i.e., all the birds died within the cluster) it would be recolonized quickly by birds from other clusters. (Noon p. S. 94). Thus, the average time between local extinctions in a cluster is of very little relevance to the long-term viability of the species.
At the hearing before Judge Dwyer, Dr. Mark L. Boyce testified that this linear regression projection probably severely underestimated the length of time that a 20-pair population would continue to live on an island. (ST 950). He believes that as the size of the population increases the length of time the population would remain present on an island would increase exponentially rather than linearly as the Committee believed. (ST 95)

2. No support from models
The only other source of information cited by the Committee to support the 20-pair HCA size was the computer model developed by Dr. Noon, together with Dr. Rollie Lamberson at the Forest Service Redwood Sciences Lab in Arcata, California. (Noon S 28) The model actually showed that cluster with 15 pairs of birds remained stable over long periods of time. (ISC Report @ 257)
Dr. Noon testified that the computer models were not the basis of the ISC Strategy and were simply used to test general concepts of reserve design rather than the specific details of the ISC Strategy. (Noon p. 114) He strongly objected to the suggestion that the ISC had relied on the models as the basis for the 20-pair HCA requirement. (Noon S 29) Nonetheless, Drs. Verner and Forsman testified that they did in fact rely on the models. (Verner S p 84, Forsman S p 24)

3. HCAs larger than necessary

Dr. Verner testified that the Committee's actual goal was to have 15 live pairs of owls in each HCA at any one time, and that because they anticipated that only three-fourths of the spotted owl sites would be occupied at any one time, it was necessary to provide habitat for 20 pairs of owls so that there would be 15 pairs present on a regular basis. (Verner S 83-86) Thus, the 20-pair size was actually an exercise in caution aimed at assuring that 15 pairs of birds would be present in each HCA.
However, having expanded the size of the HCAs to account for less than 100% occupancy of pair sites, the Committee made a second, duplicate expansion of HCA size to adjust for the very same concern all over again. Table Q-3 ISC Report at 3220 contains an adjustment factor for HCAs of different sizes depending upon the percentage of pair sites that are suitable. For 20-pair HCAs the adjustment percentage was 54%-93% depending upon how much suitable habitat is present. Thus, the number of pairs projected in the future for each HCA was adjusted downward based on Table Q-3. These adjustments are shown in the right-hand column of Tables Q-4, Q-5 and Q-6 showing the number of "adjusted future expected pairs" in each HCA in the three states.
A total of 57 of the Category 1 HCAs were made large enough so that 20 or more pairs of owls were predicted to be present in the future after applying the adjustment. (Table Q-3) Yet, according to Dr. Verner, the goal of the 20-pair size was to provide 15 pairs at any one time.
The result of this double adjustment was that all of the HCAs are at least one-third larger than the Committee judged to be necessary. While their goal was to have 15 pairs of owls present at any one time, they provided that 57 of the HCAs would have at least 20 pairs present at one time, and 15 of the HCAs will have at least 25 pairs of owls present at one time. This far exceeds the level the Committee thought necessary.
Dr. Verner confirmed that table Q-3 was intended to reflect the occupancy adjustment in the number of pairs of owls that would be present in HCAs at any one time. (Verner S. 113)
B. Distance between HCAs.
The ISC admitted in its report that it had no objective scientific bases to determine how far apart the HCAs should be. Lacking such data, the Committee used the "Delphi Method" to determine that HCAs should be no more than 12 miles apart. The Delphi Method is nothing more than a process in which a group of individuals talks about an issue until they reach a consensus on the answer to the issue. (Noon S 94)
Although the Delphi process resulted in selecting a separation between HCAs equal to the distance traveled by 67% of the dispersing juveniles, no member of the Committee could recall why 67% was selected or how that decision was reached. (Noon P 143-144)
In fact, when the HCAs were drawn on maps the average distance between HCAs was on eight miles rather than the 12-mile maximum allowed in the standards and guidelines. (Verner S 18, Noon S 101)
Committee member Joseph Lint was largely responsible for drawing the HCAs on the maps for the state of Oregon. (Lint P 15) He testified that drawing the HCAs on the maps was not a scientific exercise but a "management exercise". (Lint P 38) He testified that he could have made the HCAs farther apart and would have been within the standards and guidelines as long as they were no more than 12 miles apart. (Lint P 40-41)
C. The 50-11-40 rule.

1. Origin of the 50-11-40 rule.
Dr. Jared Verner wrote the chapter of the ISC Report, which discusses the 50-11-40 rule. (Verner P 9) When asked precisely where the biological justification for the 50-11-40 rule as explained in the report, he said, "it's not as well spelled out as we might have done." (Verner P 43) He further stated "I would agree that its' not an adequate explanation." (Verner P 150) In fact, nowhere in the ISC Report is there any explanation for the basis of the 50-11-40 rule. The 50-11-40 rule apparently received very little analysis by the ISC. The Committee was informed by unnamed "silviculturists" working for the Forest Service that current Forest Service management practices would generally produce a condition similar to 50-11-40 over a large management area (Not on a quarter township basis) (Verner P 143) Armed with that knowledge Dr. Verner testified "And so, we didn't pursue it any further. We rather assumed that this was not going to be a source of consternation." (Verner P 141)
The basic intent of the 50-11-40 rule was to lock current management practices into place in order to make it impossible for the federal land management agencies "To intensify commercial forestry in the matrix". (Thomas P 102, Forsman P 164) (The matrix is the biologist's term for the forestlands in between HCAs)
The ISC report states that the general purpose of the 50-11-40 rule is to provide "dispersal habitat" for juvenile owls as they fly from one area where they are hatched to the area which they will occupy as an adult. (ISC Report at 27) However, all of the members of the Committee candidly admit that they do not know what "Dispersal habitat" is for spotted owls. (Thomas P 104, Verner P 138, Noon P 108) Dr. Thomas said the best the Committee could do was to "make some fairly decent guesses at what dispersal habitat is". (Thomas P 104) Dr. Thomas also concede that the dispersal habitat requirement "is the weakest part, without any doubt" of the strategy. (Thomas P 124)
Dr. Thomas acknowledged that the 50-11-40 rule is not the minimum for dispersal habitat. He stated; "No, it's not the minimum guideline...I don't know what the absolute minimum is". (Thomas P 178)
Dr. Verner admits that there is not data indicating that dispersal of juvenile owls is a problem at the present time on BLM land. (Verner P 142)
Lint could draw no biological conclusion from the failure to satisfy the 50-11-40 rule one every quarter township. (Lint P 86-87) Lint testified that it was inappropriate to base a biological impact analysis on whether or not the agency was complying with the 50-11-40 rule. (Lint P 8) He testified "what you're dealing with is a recommendation...to cross over and say that recommendation is now a biological fact has biological implications of cause and effect, I would not do that" (Lint P 87) The Committee "presumed" that studies would be done to determine if the 50-11-40 standard was appropriate. (Lint P 141)
Dr. Thomas also firmly testified that he would not impose the 50-11-40 rule on private lands, even if he had the power to do so, because it is unnecessary. (Thomas P 141)

2. Lack of scientific basis for the 50-11-40 rule.
Since the ISC Report does not contain "an adequate explanation" of the basis for the 50-11-40 rule, the members of the Committee were asked to explain the basis for the rule. The explanation, uniformly, was that the rule was based almost entirely on "professional judgment" rather than on any scientific data.
a. No ecological theory supports the 50-11-40 rule. Dr. Thomas was asked, "is there any ecological theory that identifies 50-11-40 as the proper measure of dispersal habitat for spotted owls?" he replied "No". (Thomas P 117)
b. The Committee's models do not support the 50-11-40 rule.
Dr. Noon, who was in charge of computer modeling for the Committee, categorically denied that his models provided any support for the 50-11-40 rule. (Noon P 107, P 116, P 150). Dr. Noon testified that any application of his models "to real landscapes is an inappropriate use of the models". (Noon P 102-103)
c. No empirical data supports the 50-11-40 rule.

(1) No basis for 50% rule.
Dr. Thomas, the chairman of the Committee, testified that the 50% rule came from "our collective judgment " that there was "no data to support" that judgment. (Thomas P 88) Dr. Forsman said the 50% figure was "our best professional judgment - of a figure we could live with". (Forsman P 183) Lint stated it was arrived at "through consensus discussion" based on "professional judgment"/ (Lint P 79) Dr. Verner, who authored the chapter on the 50-11-40 rule, was asked what facts he relied on to select the 50% figure and replied "I guess main professional judgment at that point". (Verner P 153) Remarkably, Dr. Verner didn't seem to think it necessary to have any data to support the 50% figure, stating "I don't think the - the challenge is on us to prove that 50% is adequate." (Id at 152)

(2) No basis for 11 inch rule.
Dr. Thomas testified that the selection of 11-inch diameter trees as the minimum requirement was based on "professional judgment" rather than any particular empirical evidence. (Thomas P 204-205) Dr. Thomas stated; "That was the median that looked like a good number and we took it. That was the gist of our professional judgment" (Id at 204) Both Dr. Thomas and Dr. Verner thought that there was some support for the 11-inch rule in Table F-1 in the ISC Report, which was prepared by Dr. Forsman. However, Dr. Forsman admitted that the studies listed in Table F-1 were not studies of dispersal habitat for spotted owls. (Forsman P 148-149, P 151) Further, none of the studies mentioned in the table identify 11 inches as a minimum size for any spotted owl habitat. When asked, "Do these studies support the use of an 11-inch DBH minimum as opposed to a 10-inch minimum?" Dr. Thomas replied, "No". (Thomas P 77)

Dr. Forsman said the different studies in the report involved trees five to 20 inches in diameter and that "we made a professional judgment about what we thought was reasonable". (Forsman P 151) He agreed that none of the studies in the report specifically points to 11 inches as the proper definition of dispersal habitat. "No, in terms of picking 11 inches as a reasonable or average number from all those stands, no, not - its - 11 is not mentioned in any particular one of them as being the number, no" Id at 152-153)

Lint stated; "we settled on 11 inches as something that we felt was comfortable... it could have been 10, it could have been 12; 12 being better than 11, 10 being slightly less than 11". (Lint P 72-77) Dr. Thomas also revealed that the ISC had recently concluded that hardwood stands would provide dispersal habitat for spotted owls with no minimum tree size at all. (Thomas P 181-182) He could not explain why no minimum size was required for hardwood stands but is required for conifer stands. Id.

(3) No basis for 40% canopy rule

Dr. Thomas admitted that the 40% canopy closure figure "was largely professional judgment". (Thomas P 118, P 205) Dr. Forsman agreed that the 40% figure "was a professional judgment" (Forsman P 11) He stated that there were no studies supporting the 40% rule. Id @ 162) Dr. Verner could not remember where the 40% figure came from even though he had written the section of the report on the 50-11-40 Rule. (Verner P 155)

Lint testified that the 40 percent rule was based on "the personal experience of a lot of people in the room that had dealt with the owls". (Lint P 78) The personal experience was based on observation of adult territorial bird habitat rather than juvenile dispersal, although facilitation of the latter was the aim of the 50-1-40 rule. Id
(4) No basis for quarter township rule

The ISC requires that the 50-11-40 rule must be met on federal land in each quarter township (nine square miles). If some of the area in the quarter township is owned privately, the 50-11-40 rule must be met on the federal portion of the area. (ISC Report @ 327) Further, if an HCA is located on part of a quarter township, the area within the HCA may not be counted in determining compliance with the 50-11-40 rule. Id. Dr. Forsman testified that there were no reports or studies, which support the requirement for 50-11-40 rule to be applied on a quarter township basis. (ForsmanP 190-191)

Dr, Verner conceded that the intent of the 50-11-40 rule is met if the quarter township as a whole satisfies the 50-11-40 rule even if the federal ownership within the quarter township does not meet the rule. (Verner P 148) Neither Dr. Verner nor Dr. Thomas knows how much dispersal habitat exists today on the intermingled private lands. (Verner P 145, Thomas P 138) Dr. Thomas admitted that he doesn't know how many quarter townships of intermingled BLM and private lands meet the 50-11-40 rule today, and that no member of the Committee had ever looked into the question. (Thomas P 139) Dr. Noon was not real knowledgeable" on quarter township issue. (Noon P 167-168)


The two computer models developed for the ISC were heavily relied on by the Committee in selecting the 20-pair minimum HCA size and to support the entire conservation strategy. Yet the creators of the model never intended them to be directly used to develop strategy, and the models fail to provide any direct support for the ISC Strategy. In fact, the models could equally support a conservation strategy with one-quarter as much land set aside for spotted owl habitat.

Dr. Barry Noon was the committee member responsible for the models. However, he denied authorship of the models, attributing them to Dr. Rollie Lamberson and claiming only a secondary role for himself. (Noon P 45, P 51) Work on the "cluster" model, which is cited to support the HCA concept began after the ESC began its deliberations, an there was never any written description of the model other than in the ISC Report. (Noon P 46-47) No one on the Committee or outside the Committee ever evaluated the structure of the model. (Noon P 48)
Dr. Noon testified that model should only be used to test general principles of reserve design, and that it would be "inappropriate" to apply the models to the real world, (Noon P 102-103) He has come to doubt the assumptions in the cluster model and has been revising the model using different assumptions. (Noon P 68) He has no data to support the assumption in the model. (Noon P 69) The cluster model does not reflect any real landscape that Dr. Noon is aware of. (Noon P 55) and the model cannot determine the minimum population size required for viability. (Noon P 87)

The key assumption in the cluster model is that a juvenile spotted owl is more likely to successfully disperse to a new home within a cluster of habitat sites than between clusters. It is this assumption which justifies the entire concept of an HCA and many sites clustered together as opposed to the SQHA system of scattered individual sites. However the HCA had no data to support this assumption. (Noon P 67, P 69)

Further a key variable in determining how large a cluster must be and how far apart it should be from other clusters is the "search efficiency" of a dispersing Janesville owl (the number of sites a dispersing owl can visit in search of a home before dying) However, the actual search efficiency of juvenile owls is unknown. (Noon P 88) Thus, the model cannot predict how many owls are required to maintain viability. (Noon P 89)

The cluster model also assumes that a juvenile spotted owl cannot settle as a "floater" in a territory that is already occupied by a pair of owls, even though biologists know that this commonly occurs. (Noon P 92) If the model had been adjusted to reflect this reality, it would have resulted in a higher survival rate for juveniles. (Noon P 93) and this measure would be key to evaluating any proposed conservation strategy. (Noon P 94) This adjustment would have supported smaller HCAs farther apart.

The model also assumes that there are no breeding pairs of spotted owls outside the HCAs which Dr. Noon recognized as "unrealistic'> (Noon P 113. P116) The model further assumes that only 80% of the spotted owl's sites are occupied at the beginning of the model run. A species is normally assumed to be present in numbers sufficient to occupy all of its available habitat (known as "carrying capacity". If the model had assumed that owls were at 100% of their carrying capacity, smaller HCAs farther apart would have produced the same level of viability as larger HCAs at 80% of carrying capacity.

The model does not assume that every acre of spotted owl territory is suitable spotted owl habitat, it merely assumes that there is enough suitable habitat within a territory so that a pair of owls can successfully occupy it. (Noon P 111) Thus, the model provides no support for the ISC Strategy's prohibition on all timber harvesting within HCAs. (the empirical data also fails to show a need to prohibit all harvesting within HCAs Forsman P 145)
The model also does not support the proposition that every territory within the HCA must be viable for spotted owls. To the contrary, the model showing that an HCA in which 60% of the sites were suitable for owls was just as effective in maintaining a viable population of owls as an HCA in which 100% of the sites were suitable. (Noon P 122)

The ISC Report itself found that a site with 40% suitable habitat is just as effective in supporting a reproducing pair of spotted owls as a site with 100% suitable habitat. ISC Report at 183 (relying on Bart and Forsman unpublished 1990) Thus, the cluster model would provide just as much support for a conservation strategy proposing HCAs in which 12 sites out of 20 were suitable habitat. Under this alternative strategy only 24% as much habitat would have to be preserved to provide as many spotted owls as under the ISC strategy.


Some of the HCAs in Oregon are placed in areas of checkerboard ownership of 50% BLM and 50% private land. Other nearby HCAs are 100% Forest Service land. The ISC Report projects the same number of owls per acre on checkerboard HCAs as on the 100% federal HCAs, even though the report specifically states that timber harvesting on the private lands within the HCAs is not constrained in any way.

Eric Forsman endorses the judgment that an HCA with 50% checkerboard federal land is just as effective in providing habitat for spotted owls as nearby HCA composed of 100% federal land. (Forsman P 276-78) Barry Noon confirms that the cluster model projects that a cluster with 50% suitable sites is just as effective as a cluster with 100% suitable sites as long as there is a capacity of 25 pairs of owls. (Noon P 188)

A. The ISC Report contains contradictory analysis of population trends.

1. Packing.
Far more spotted owls have been observed in the past five years than were know to exist previously on the highly fragmented checkerboard BLM timberlands in western Oregon. In 1985 only 100 pairs of owls were known to be present on those BLM lands, while in 1990, 500-700 pairs were observed.

However, the ISC discounted these population reports completely. The ISC Report states that the spotted owl population in the Roseburg BLM district, which is the only heavily studied BLM area, was declining at 14% a year, and the reason that more owls were observed year after year was due to timber harvesting. ISC Report at 235-237 points to packing as the explanation for the increased number of observed owls.

At the same time, the report also places great reliance on the habitat study prepared by Jonathan Bar and Eric Forsman, which compares densities of owl populations in different proportions of older forest. It relies heavily on this study in finding that a large proportion of older forest is required for spotted owls. ISC Report, Appendix G. The US Fish and Wildlife Service listing decision also relies heavily on the Bart and Forsman paper.

The Bart and Forsman paper however, is based on the assumption that packing is not occurring at the present time. (Forsman P 24) It assumes that the relative density of owls in different types of habitat is a reflection of the suitability of those types of habitat. Thus, the Committee assumed at the same time that packing is and is not occurring. Both cannot be true.

If packing is occurring, it should be evidenced by declines in reproduction and survival rates where packing is occurring. (Thomas P 60) Dr. Jack Ward Thomas who has never conducted any on -the-ground spotted owl research believed that the reproductive rates are declining on the Roseburg BLM district. (Thomas P 62) However, Dr. Forsman, who is conducting the research on the Roseburg BLM district testified that the reproductive rates and the survival rates are not declining on the Roseburg district. (Forsman P 245). He has no evidence that the reproductive rate or survival rates of the spotted owl are declining anywhere in its range at the present time. (Forsman P 246)

2. Population trends on the Roseburg BLM district.

The ISC Report presents a demographic analysis which suggests that the spotted owl population on the Roseburg BLM district is declining at the rate of 14% per year. (ISC Report at 234) The Committee appeared to place great significance on this presumed rapid decline in population. (Noon S 80-81) However, both the Committee members who conduct the on-the-ground research on the Roseburg district disbelieve that projection. Dr. Eric Forsman does not believe that a 14% per year decline is occurring, but thinks that the rate of decline is closer to 2% per year. (Forsman P 236-237) He discussed his concerns with Dr. Noon, who prepared the 14% analysis, and pointed out that the 14% figure might be too high because the last year of data banding study is always less reliable than data from previous years. (Forsman P 215-216, P 238-239) He doesn't know why this problem was not disclosed in the ISC Report. (Forsman P 239) Dr. Forsman himself had reported ' an insignificant change" in the population on the Roseburg district between 1988 and 1989 in his own research report, a finding that is not consistent with the 14% annual decline. (Forsman P 240-241) (His findings could be consistent if packing were occurring but Dr. Forsman along with Dr. Bart does not believe that packing is occurring at the present time)
In 1990 there were 151 confirmed pairs of owls on the Roseburg district plus 46 single owls, for a total of 348 owls. If there were a 14% decline per year occurring on the Roseburg district between 1985 and 1990, there would have been over 670 owls on the Roseburg district in 1985. Dr. Forsman does not believe that there were over 670 spotted owls on the Roseburg district in 1985. (Forsman P 244) This number "doesn't fit with my experience". ld.
Joseph Lint, who has worked on the Roseburg district for almost a decade, confirms that he supervised a survey of Roseburg district BLM data which indicated an annual decline of 2% per year rather than the 14% suggested in the ISC Report. (Lint P 154)

3. Fragmentation

The ISC Strategy is based on the Committee's belief that habitat fragmentation causes serious harm to spotted owls. (ISC Report P 22-23 Thomas P 53) However, none of the members of the Committee knew of any studies, which showed that fragmentation of habitat harms spotted owls. While Dr. Thomas was sure that the Committee's analysis of fragmentation studies was "very carefully worked out in the report" (Thomas P 53) Dr., Verner hedged his answer with the statement that "Fragmentation is exceedingly difficult to study". (Verner P 105) He believes that the best study on fragmentation has been done by Mark Boyce and Joe Meyer. (Verner P 106) Dr. Noon agrees that this is the best study of fragmentation, (Noon P 79) Dr. Boyce testified at the Seattle Audubon Society hearing that his study had not shown that fragmentation of habitat has any harmful impact on spotted owls (ST 941-942)

No study has ever shown that fragmentation of habitat has any harmful impact on spotted owls.


The ISC Strategy is not the objective, verifiable scientific product its proponents have held it to be. The Committee ignored the huge gaps in empirical data, the lack of relevant scientific theory and the unreliability of the population simulation models, and based the Strategy largely on the collective professional judgment of its members. Each of the three key components of the ISC Strategy - the size of HCAs, the distance between HCAs and the 50-11-40 rule is primarily the professional judgment rather than data, theory or model. (Joseph Lint, who was the only Committee member to do any of the actual map drawing denied that the map drawing process was a scientific exercise, labeling it "a management exercise".

The Committee evidenced confusion or misunderstanding on such key issues as fragmentation, packing and population trends. It left behind no record of its deliberations to allow subsequent researcher to recompute and verify its calculations or to resolve the contradictions and inconsistencies, which now appear in the report. The ISC Strategy should not and cannot be viewed as the last word on the spotted owl. Policy makers, administrative officials and legislators who are charged with the legal responsibility to make final management decision on the spotted owl should view the ISC Report as nothing more than a tool to assist them - a tool which must be used properly and with full understanding of its limitations.



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