Discussion

Let us know what you think about any topic related to the Sierra Nevada Adaptive Management Project in the forums below. The Principal Investigators on the UC Science Team cannot answer every post, but they will read all comments in their areas, and respond to comments as a group at each quarterly meeting. We greatly value your input!

Owl Team response to questions from Steve Brink, 10/4/2012 by Kim_Ingram, at 3:33 p.m. on 4 October 2012,

The following are questions and responses regarding the CA spotted owl: Q1:Since 1993, the owl team stated that they have surveyed roughly 90% of the DSA each year. This was determined by placing a 1/2 mile buffer around each of the recorded survey points. Would it be possible to determine the % "covered" for each year 1986 through 1992 using the same methodology? If so, can the percentage of coverage be provided?

A1: We previously estimated the survey coverage on the Eldorado Density Study Area (EDSA) for the years 1989-1992:

1989: 78% 1990: 82% 1991: 86% 1992: 91%

Although the coverage was reasonably high in these years, many portions of the EDSA were only surveyed once per year from 1989-1992 because we did not have sufficient funding to hire an adequate number of technicians. This lack of survey effort made it more likely that we failed to detect owls that were actually present. 1993 was the first year that we conducted more than 1 survey at >90% of our survey stations.

Q2:Could the occupancy analysis be run on the owl sites that were first found in the study area from ~1986 through 1992? Has the occupancy rate for those owls sites dropped as well? Premise of question: The range -wide high reproductive year of 1992, (most likely due to abundance of prey and very mild spring weather) also lead to a high survival rate (young and adult) and potentially a population that was above the carrying capacity of the landscape. The population in 1993 with nearly 100% occupancy has been slowly adjusting back "down" to the “normal or potential” carrying capacity of this landscape.

A2: We appreciate Mr. Brink’s suggestion, but we currently lack the time and resources to pursue an occupancy analysis for the years 1986-1992. As we stated at the Owl IT meeting in August, we chose 1993 as the starting point of our analysis because it was scientifically defensible. In other words, a peer reviewer could assert that any observed occupancy trends were confounded by changes in survey effort if we used data prior to 1993.

We also question his premise that a single year (1992) of high reproductive output is still affecting our study population 20 years later. Spotted owls are long-lived, but with an annual survival rate of ≈ 0.83, it is unlikely that a birth pulse would continue to influence population trends 20 years after the pulse.

Questions for SNAMP Owl Team by Kim_Ingram, at 11:21 a.m. on 20 September 2012,

The following questions have been submitted by Steve Brink in response to the SNAMP Owl team's IT meeting in August 2012:

Q1)Since 1993, the owl team stated that they have surveyed roughly 90% of the DSA each year. This was determined by placing a 1/2 mile buffer around each of the recorded survey points. Would it be possible to determine the % "covered" for each year 1986 through 1992 using the same methodology? If so, can the percentage of coverage be provided?

Q2)Could the occupancy analysis be run on the owl sites that were first found in the study area from ~1986 through 1992? Has the occupancy rate for those owls sites dropped as well? Premise of question: The range -wide high reproductive year of 1992, (most likely due to abundance of prey and very mild spring weather) also lead to a high survival rate (young and adult) and potentially a population that was above the carrying capacity of the landscape. The population in 1993 with nearly 100% occupancy has been slowly adjusting back "down" to the “normal or potential” carrying capacity of this landscape.

Owl team response to questions from Steve Brink by Kim_Ingram, at 11:36 a.m. on 6 September 2012,

The following response is from the SNAMP Owl team to questions submitted by Steve Brink after the IT meeting of 8/23/2012:

Q1:Looking again at the Lambda graph, it’s interesting that the downward slope of the line is nearly constant. I should have thought about the 2001 Star Fire when Pat Ferrell, Eldorado NF Contracting Officer, asked a question about it. The Star Fire burned 16,900 acres in Aug-Sept. 2001, about 2,400 acres of which were on the Georgetown Ranger District. Following the fire, the USFS concluded that the two HRCAS, in which PAC055 and PAC075 were located, were essentially destroyed and recommended deleting both PACs from the Forest plan. Further, about 70% of the total acres burned in the Fire were of high severity. So, how is it that the Star Fire had absolutely no affect on the owls?

Response: First, recall that Doug noted that the estimates for lambda are based on model averaging (the average estimate of several models), which results in the smooth (“constant”) curve to which you refer. As long as the declining trend is not abrupt, it will appear relatively smooth despite slight variation in the annual estimates. Second, the two owl territories affected by the Star Fire were Regional territories, and the lambda analysis only included owl territories on the Density Study Area. Even if the two owl territories affected by the fire had been located on the Density Study Area, the observed impact would not have been dramatic because there are 45 owl territories on the density study area. In addition, we note that about 2,500 acres did burn on the Eldorado Density Study area during the Star Fire. This burn affected 3 owl territories on the density study, but all have been occupied at least once since the fire.

Q2: Because soil site classification could be used as a surrogate for the overall “primary productivity” of a forest, will the samples for the control and “treatment” areas be stratified? The premise being that owls in highly productive forests will perform better under both the control and “treatment” conditions, and likewise owls on less productive forests will underperform under control or treatment scenarios.

Response: This was suggested in the context of including “abiotic” factors as covariates in our analysis, which we think is a good idea. The idea of including soil type is a good one and we will consider that thoroughly for our list of covariates.

Q3: It’s still unclear to me why the Team is not opportunistic and looking to tease out why Owls had very high reproductive success in 1992. Using the 1993 data, and not using 1992, doesn’t seem intuitive given Rocky’s premise that CSO’s live a long time and have an evolutionary strategy that is opportunistic for reproduction. How can that be justified?

Response: The owl team has often wondered why there was such high reproduction in that year. The problem is that there is that there have been no other years such as 1992 to make comparisons. In other words, if you found several factors that were different in this year relative to other years, how would you distinguish which was consistent in terms of its importance to owls? One needs to have multiple examples of unique events to detect a pattern. In addition, 1993 was the first year that we had good aerial photography for the entire study area and adequate sampling effort to have confidence in detecting reproduction and a sufficient number of surveys over the entire study area. We note also, that unlike what was implied in our presentation, we do have air photos prior to 1993 but they are not seamless digitized photos as in 1993. Thus, it is quite time consuming to work with these other photos. It is important for the record to note that all of the effort to create vegetation maps by the owl team for the past dozen years in order to assess impacts has been done, until last year, without funding. That is, we have no allocated money to engage in this activity, but all the owl investigators have devoted their own time to create such maps because we realize the importance of the information. We continue to assess sources of air photographs that are easily used and welcome any help the SNAMP stakeholders are able to offer.

Q4: Given how robust the IPM is, why wouldn’t Doug include ALL of the owl data that the Team has including: 1)The discrepancies related to the 8 birds that were counted in the occupancy but not as part of the population and likewise the other 4 birds that resisted capture? 2)The 1992 reproduction data since it is congruent with Rocky’s premise that the evolutionary strategy of the owl is to be long lived and be opportunistic for reproduction? 3)Running a comparison with and without the 1992 data?

Response: “All” of the birds, including the ones referred to in part 1 of this question, are incorporated into the IPM through the count data. The count data are the number of birds detected each year on the Density Study Area, regardless of whether the birds are marked or unmarked. Doug chose 1993 as the starting year for all of his population trend analyses because that was the first year that we achieved adequate survey coverage of the Density Study Area. As Doug discussed, it is critical that the study area be consistent in size when assessing population trends because the number of birds in the population is a direct function of the size of the study area. The 1992 data are consistent with the hypothesis that spotted owls have evolved a “bet hedger” life history strategy, but so are many other features of their life history (such as long life span, low fecundity). So the 1992 data are interesting but they do not make or break any analysis we do. They are interesting and we are curious, like you, as to why we have not seen similarly high reproduction years since then. However, these data as a single event do not provide insight into changes in owl populations other than to demonstrate that unusually high years of reproduction do occur infrequently.

CA Spotted Owl IT follow up questions by Kim_Ingram, at 1:05 p.m. on 27 August 2012,

The following questions have been submitted by Steve Brink in response to the Owl IT meeting on 8/23/2012:

Q1: Looking again at the Lambda graph, it’s interesting that the downward slope of the line is nearly constant. I should have thought about the 2001 Star Fire when Pat Ferrell, Eldorado NF Contracting Officer, asked a question about it. The Star Fire burned 16,900 acres in Aug-Sept. 2001, about 2,400 acres of which were on the Georgetown Ranger District. Following the fire, the USFS concluded that the two HRCAS, in which PAC055 and PAC075 were located, were essentially destroyed and recommended deleting both PACs from the Forest plan. Further, about 70% of the total acres burned in the Fire were of high severity. So, how is it that the Star Fire had absolutely no affect on the owls ?

Q2: Because soil site classification could be used as a surrogate for the overall “primary productivity” of a forest, will the samples for the control and “treatment” areas be stratified? The premise being that owls in highly productive forests will perform better under both the control and “treatment” conditions, and likewise owls on less productive forests will underperform under control or treatment scenarios.

Q3: It’s still unclear to me why the Team is not opportunistic and looking to tease out why Owls had very high reproductive success in 1992. Using the 1993 data, and not using 1992, doesn’t seem intuitive given Rocky’s premise that CSO’s live a long time and have an evolutionary strategy that is opportunistic for reproduction. How can that be justified?

Q4: Given how robust the IPM is, why wouldn’t Doug include ALL of the owl data that the Team has including: 1) The discrepancies related to the 8 birds that were counted in the occupancy but not as part of the population and likewise the other 4 birds that resisted capture? 2) The 1992 reproduction data since it is congruent with Rocky’s premise that the evolutionary strategy of the owl is to be long lived and be opportunistic for reproduction? 3) Running a comparison with and without the 1992 data?

Steve Brink California Forestry Association

CSO - site occupancy definition by Kim_Ingram, at 11:33 a.m. on 6 February 2012,

Can you provide a "working" definition the researchers are using for spotted owl occupancy. Is it simply occupancy (i.e. owl presence) or is it pair occupancy, or something else? Thank you for your time and consideration with this question. Kevin Roberts Wildlife Biologist Sierra Pacific Industries

The determination for occupancy is the presence or absence of an owl that is corrected for detection probability. It can be a single owl or a pair. Rocky Gutierrez - SNAMP Owl team Kim Ingram - PPT team

Owl team response to population decline question by Kim_Ingram, at 1:25 p.m. on 3 November 2011,

Dear Ms. Dobrovolny:

At the annual SNAMP meeting, I explicitly stated that I did not know what is causing this recent (past 10 years) owl decline. Our research suggests that the decline is real based on two different estimators producing the same result. I was also asked by a participant at the meeting if fuel treatments might be the cause of the decline and I said that I did not know because there were other factors that might be involved such as clear cutting on private land. By logical extension, this would apply to home development as well, as you suggested in your letter. Recall that the owl component of Last Chance includes the entire Eldorado spotted owl density study area, which encompasses a much larger area than Last Chance and has many more owl territories. Because of the uncertainty about the cause of the decline, the owl team has proposed a retrospective study to examine all observable changes in owl habitat that were due to disturbance. Presumably this would allow us to account for different types of disturbance, which would address one of your concerns. Our inference would be restricted to our study areas because we are not measuring change or monitoring owls throughout Eldorado County although our study areas might be a representative sample of this population. In addition, because of severe budget limitations, I doubt that our study could be expanded to include all of Eldorado County.

Sincerely,

R. J. Gutierrez, Professor and Gordon Gullion Endowed Chair in Forest Wildlife Research

CA Spotted Owl population questions by Kim_Ingram, at 9:38 a.m. on 3 November 2011,

The following comments and questions were asked by Lorna Dobrovolny from CA Dept. of Fish and Game:

'I work with Cal Fire foresters on wildlife issues in El Dorado County resulting from forest fuel reduction projects. There are no longer any DFG staff on timber harvesting review teams as a result of state budget cut-backs. California spotted owl has only a Species of Special Concern status. Thus, very limited regulatory protection from projects on private forest lands. I was very interested and concerned about Rocky's findings regarding spotted owls. There has been substantial timber harvesting and population expansion in the early to mid 2000s during the housing boom in El Dorado County. I'm not sure how the SNAMP research can outline a study plan to definitively show that it's the Last Chance fuel break that would be impacting the birds, given a demonstrated existing decline. Do you know how this is going to be accounted for? Also, the USFS and CAL FIRE have given much grant money to forest land owners in the past, mostly to tie together ridgetop fuel breaks for fire prevention. Most of that work was mastication, the result of which may not offer spotted owls suitable habitat."

Thanks for you comments and questions Lorna.

Planes Used in Fisher Research Flights by Anne Lombardo, at 1:49 p.m. on 22 September 2011,

At the presentation to the Alpine Village Association in Fish Camp on September 5th, 2011, the following question was raised by one of the participants. The project leader for the SNAMP Fisher Study Rick Sweitzer's response follows.

Question: "What kind of plane does Rick use to track fisher in?"

Answer: "As for the airplanes: All of our planes are tailwheel design planes for maximum safety in the event of an emergency back country landing. Our primary plane is a Cessna 185 outfitted with a stol kit and airfoil fins along the edge of the wing. These modifications are designed to improve lift and maneuverability for the kind of flying we do. Out backup plane is a Piper Supercub, also with airfoil fins along the leading edge of the wings. At present we have a Husky that we are using as a backup airplane while the Supercub is being recovered."

Weasel at 9000 feet by Anne Lombardo, at 8:53 a.m. on 1 September 2010,

In regards to the weasel you saw at 9000 feet. We think you might have seen a marten as they tend to live above the fisher in elevation. We've posted a few pictures of martens taken from our motion cameras for you to compare:

A fisher near sunrise camp? by netkat, at 9:48 p.m. on 30 August 2010,

On my way to Sunrise Camp in Yosemite over the weekend, in the trees on the edge of the meadow about 1 mile from the Sunrise Camp, I saw a very unusual animal. It had a smallish head (rather like a weasel) and was long bodied with a black tail. From the photos I've been able to find, it seems the animal resembles a fisher but the elevation where I saw this animal was about 9000 feet. Could it possibly have been a fisher? If not a fisher, what else could it have been. Definitely was not a marmot (as I had seen one earlier in the day).

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