NINTH ANNUAL MEETING ISLAND FOX WORKING GROUP Sheraton Four Points Hotel, Ventura CA JUNE 19 TH 21 ST, 2007

Transcription

1 NINTH ANNUAL MEETING ISLAND FOX WORKING GROUP Sheraton Four Points Hotel, Ventura CA JUNE 19 TH 21 ST, 2007 Sponsored by: National Park Service US Fish and Wildlife Service The Nature Conservancy California Department of Fish and Game Catalina Island Conservancy Friends of the Island Fox SUMMARY REPORT Prepared by Cathy A. Schwemm July 31, 2007

2 Summary Report, Island Fox Working Group Annual Meeting TABLE OF CONTENTS ABSTRACTS AND SUMMARIES OF SCHEDULED PRESENTATIONS Status of the Island Fox Recovery Plan... 4 Eric Morrissette San Nicolas Island Update... 5 Grace Smith Status of the Catalina Island Fox... 5 Julie King Santa Cruz Island Update... 7 Rachel Wolstenholme Status of Santa Rosa Island Foxes... 8 Tim Coonan Status of San Miguel Island Foxes... 9 Tim Coonan Mainland Populations Update Alan Varsik Island Fox Health Issues Linda Munson and Winston Vickers Reproductive Failure Monitoring: Results and Recommendations Cheryl Asa, Deana Clifford, Winston Vickers, Betsy Calkins, and Karen Bauman Contemporary Evolution in the Santa Cruz Island Fox Hilary M. Swarts, Kevin R. Crooks, Neil Willits and Rosie Woodroffe Feasibility Study for Feral Cat Removal on San Nicolas Island Brad Keitt and Annie Little Automated Telemetry System for Island Foxes Dave Garcelon Fecal Genotyping for Monitoring Island Foxes Melissa Gray San Clemente Island Fox Ecology Bill Andelt Endangered Species Recovery Planning Mike McCrary Biological Underpinnings of Recovery Criteria Dan Doak Overview of Island Fox Population Dynamics and Final PVA Results Vicki Bakker and Dan Doak Using the PVA to Guide Recovery Criteria Dan Doak and Vickie Bakker Population Monitoring: Development of a Monitoring Plan and Recommended Protocols Esther Rubin WORKGROUP SUMMARIES Non-Target Impacts to Island Foxes Within the Scope of Feral Cat Removal on SNI: Solicitation of input from IF Working Group

3 June, 2007 Wild Population Management and Recovery Planning Group Captive Breeding Working Group Fox Health Working Group FINAL PLENARY SESSION APPENDICES Appendix A Meeting Agenda Appendix B Summary Table of Population Status by Island Appendix C Recommendations for Parasite Treatment of Dogs Leaving Santa Cruz Island Appendix D 2007 Meeting Attendees The following island designations will be used throughout the report: San Miguel Island (SMI), Santa Rosa Island (SRI), Santa Cruz Island (SCI), Santa Catalina Island (CAT), San Clemente Island (SCL) and San Nicolas Island (SNI). 3

4 Summary Report, Island Fox Working Group Annual Meeting ABSTRACTS AND SUMMARIES OF SCHEDULED PRESENTATIONS Status of the Island Fox Recovery Plan Eric Morrissette, US Fish and Wildlife Service The Draft Recovery Plan draft is under development by the Recovery Coordination Group (RCG), which when finished will be submitted to the Fish and Wildlife Service (USFWS) for review. In May the RCG requested comments from the Technical Expert Group (TEG) chairs and representatives from the land management agencies. At that time the TEG chairs and land managers were given the discretion to seek input from additional experts in preparing their comments. The Federal Advisory Committee Act (FACA) prevents a federal agency from getting advice from a limited subset of the public. The RCG is exempted from FACA because they have been charged with the development of the Draft Recovery Plan. The Integrated Recovery Team (aka Island Fox Working Group [IFWG], this group), is not exempted from FACA. Because of FACA and its associated limitations on receiving advice from a limited subset of the public, the Draft Recovery Plan cannot be distributed to the IRT while it is under development. At this point comments have not been received from all the land managers and TEG reviewers, so the RCG requested and received an extension for preparation of the draft until August 1 st. At that time USFWS will conduct an internal review within the local (Ventura) office. When that is completed the draft will be transmitted to the USFWS regional and national offices for review, a process that is anticipated to take 4-6 months. The Draft Recovery Plan will then be available for public comment (minimum period of 60 days), after which the USFWS will address all submitted comments. If necessary at this point the USFWS can seek additional expert input to address comments. The Final Recovery Plan will then hopefully be released months after the close of public comment, putting the publication around the spring of Audience questions/comments: - What is the current role of the IRT? Eric responded they are considered experts, but are not part of the formal recovery team. But apparently there is some misunderstanding about the relationship between the RCG and the IRT. These meetings (IRT-IFWG) are considered public meetings, so structurally the attendees can t be considered part of the formal Recovery Team. However, these experts can be consulted by the TEG chairs, the RCG, and the land managers. - How will/can the results from this meeting be incorporated into the plan? The RCG can use the information presented here in any way they feel is appropriate. However, to be certain that the RCG gets all relevant information, specific items or recommendations should probably be formally transmitted to the RCG through the TEG chairs. (So it is probably a good thing that the draft recovery plan period has been extended; information from this meeting can now be included as appropriate as the RCG completes the draft.) There was an additional response from some RCG members present that they want as much input as possible while staying within FACA. And the RCG will look toward the TEG chairs to transmit information. 4

5 June, Point of Information, the TEG chairs are: Colleen Lynch Genetics, Peter Siminski Captive Populations, Kathy Ralls Modeling, Scott Morrison Wild Populations, Linda Munson Animal Health, Sandy Vissman Eagle Management, Dan Blumstein Reintroductions, and Lyndal Laughrin Ecosystem Restoration. San Nicolas Island Update Grace Smith, US Navy, San Nicolas Island The results of the 2006 IF monitoring conducted by the Navy and the Institute for Wildlife Studies (IWS) were presented. Background information on San Nicolas Island (SNI) was also presented; it is used as a platform for missile launches as part of Navy training exercises in the surrounding waters (approx. 36,000 mi-square). There are personnel permanently assigned to the island. Foxes have been monitored on 3 grids since 2000, and a description of grid vegetation types was presented. Trap spacing is 250-m and trapping is conducted for 6 nights. The results were presented, with an island-wide estimated density of 8-18 foxes/km 2. The age class structure was presented, and population growth rates were calculated at >1.0. The island-wide population estimate was derived by interpolating the densities on each grid to the area of similar vegetation types across the island. As in the past, SNI has the highest grid-based density estimates of any IF sub-species. Moreover, the population appears stable, and there are currently no significant health concerns. Other research and management efforts on SNI include the vaccination of 26 foxes in 2006 for distemper and rabies, the development by IWS of an automated telemetry system (described in a separate presentation), and the initiation of a study to determine pregnancy rates and neonatal status. Regarding human-caused mortalities, there were many fewer traffic mortalities on the island than in previous years, however there were 3 foxes that died after being trapped in structures, and 7 additional mortalities from unknown causes (all age class 4). Audience questions/comments: - What are the freshwater sources for foxes? Mostly fog-drip; there is very little surface water. Status of the Catalina Island Fox Julie King, Santa Catalina Island Conservancy Abstract Wild population monitoring on Catalina included island-wide trapping and aerial telemetry. A total of 330 unique individuals were captured during the main island-wide trapping effort occurring July 17-Oct 20, 2006 with an additional 8 animals captured during post island- wide target trapping. The estimated population was 509 (336 EE [East End]: 173 WE [West End]) with a mean island-wide population density of 3.31 foxes/km 2 (EE = 2.43 foxes/km 2 ; WE = 7.24km 2 ). A total of 295 of 338 (87%) wild foxes were vaccinated against both rabies and CDV and a total of 55 radio collars were deployed. Twenty-five of the 55 radio-collared animals were not vaccinated and will serve as disease sentinels. Weekly aerial telemetry monitoring for mortality was conducted throughout the year. Captive breeding ceased in 2004, however 5 animals remained in captivity during The 3 geriatric captive animals diagnosed with ceruminous gland carcinoma (ear tumors) were euthanized in September based on declining 5

6 Summary Report, Island Fox Working Group Annual Meeting health. The 4 th captive animal, a 2004 released male had spent the year recovering from an injury and was released October 31 st. Tachi, the educational fox remained the only animal in captivity by the end of Twelve known mortalities were recorded during the year, with vehicle collision being responsible for 5 of 12. A fire occurring on May 10 resulted in 4,750 acres (10% of the island) being burned with a single known fox being severely injured and subsequently treated. Twenty GPS collars (Televilt Tellus Mini C3) will be deployed during 2007 to gather home range and habitat use of foxes both in the burn and outside of the burned areas. Additional notes - Aerial surveys allow detection of all collared animals on the island in less than one hour. - Current threats include vehicles, feral cats, domestic dogs, human practices, and disease (ear tumors). - There have been 11 known mortalities so far in 2007, but this number is likely an artifact of greater detection rates resulting from more deployed collars. - The Conservancy has installed road signs similar to those used on SNI and will be installing speed detectors. They will also implement a pet policy for interior residents and camp lessees. - The City of Avalon has established a feral animal task force on which the Conservancy and IWS (Winston) are trying to have a strong presence. - Coordinated research between IWS and UC Davis was initiated on health issues, specifically ear tumors. All field personnel now carry otoscopes so the detection rate of ear tumors in the field is more accurate. - The restoration plan for the fire is still being developed, and the Conservancy is hoping that it will prescribe the use of natural features to minimize mud slides without reseeding. If reseeding does occur it will be with native species only. - Injuries to animals resulting from the fire included one bison that was euthanized, and one fox with paw burns. This fox was very emaciated when it was caught, but responded well to treatment and hopefully will be releasable. - Examination of the burn area with last year s monitoring data revealed 31 animals that were potentially using that area. Directed trapping caught 15 adult foxes and no pups, and these animals had no observable injuries. They caught several lactating females which indicates that pups and moms were still together in the area and doing well. They are also looking at deploying the new GPS collars inside and outside the burn area; however these can only be put on animals > 2.5 kg (there are many animals in this class). Most of the collars will go on east end animals. - Pressing fox management issues on Catalina include: 1) decision-making regarding euthanizing animals with ear tumors; clearly there are humane considerations, but keeping those in mind there are also benefits of study at later disease stages; 2) decision-making regarding when/if to release injured animals. For example the animal with the injured leg was released because it was doing well, but died the following spring from as yet undetermined causes. (In the past a major source of mortality to released animals was vehicle trauma.) Audience questions/comments - How much do GPS collars weigh? Just under 70 g; the cost is $1,200/each. They are fortunate to have a donor base on Catalina that will sponsor these needs. 6

7 June, What is life of these collars? Depends on how often they collect data, they estimate 3-7 months collecting every 3 or 6 hours. And can also adjust how often the UHF beacon comes on to transmit, which will also affect longevity of the collars. - Question about locations of fires in last 100 years, and whether or not they have been mapped. Answer that if the location was known it has been recorded, but no analysis of fire history has been done as far as they know. Santa Cruz Island Update Rachel Wolstenholme, The Nature Conservancy Abstract The Nature Conservancy, the National Park Service, and the Institute for Wildlife Studies conducted island fox recovery efforts on Santa Cruz Island that included wild fox abundance and distribution assessment, captive breeding, and survival monitoring of wild and captive-reared foxes. Transect trapping (covering an estimated 41% of the island and conducted from late June through September) resulted in the capture of 143 individuals (67F: 76M), 58 of which were young of the year. An additional 55 individuals were captured during targeted trapping conducted through the fall. Between July and November 2006, 56 foxes were released from the two captive breeding facilities during five releases. Thirteen pups were born to seven pairs in captivity, ten of which survived to emerge from their dens. As of June 2007, there are 33 foxes in captivity (23 adults and 10 pups). All captive foxes are housed at the Navy site facility on NPS property. We monitored a total of 135 foxes (79 wild; 56 captive reared) for survival at least once per week in The combined annual survival rate for all foxes was 70.8% (82.1% from July through December 2006 and 63.6% from January through June 2007). The annual rate for released foxes (57.6%) differed from wild born foxes (82.5%) (V. Bakker, pers. comm.). Additional Notes - Approximately 1/3 of the trapped animals were collared - Two females that had fetuses on ultrasound did not produce live pups; an additional two females considered not pregnant did give birth. - Post-release monitoring did not detect any animals that required re-capture - There are currently 73 collared animals. Of these many of the wild-born are on the middle of the island, while most of the captive-born are on the east and west ends, near their release sites. - Total mortality of collared animals was 25 (17 captive-reared), with 21 from golden eagles (GOEA). All of the GOEA mortalities were on the western 2/3 of the island, mostly to the far-west. Two released animals died from causes other than predation. - In the spring of 2007 GOEA surveys included helicopter (ProHunt) and ground survey work. Checked all known and historic nests by helicopter, but no birds were found. The helicopter responded to all unknown raptor sightings and flew every day during 3 separate week-long surveys, including several flights to SRI, without a sighting. These efforts will continue, although the ProHunt helicopter will be gone soon. - Trapping will continue this summer, and the possibility of releases this year is still being discussed. 7

8 Summary Report, Island Fox Working Group Annual Meeting - A total of 5036 pigs have been removed, with the last observation of an un-collared pig in July The island is therefore currently ecologically pig-free. Audience questions/comments - Have there been confirmed GOEA sightings this spring? One in February, and maybe one the first weekend in March by a reputable raptor biologist. - How many (wild?) pup mortalities? None. - What is the evidence that it is GOEA and not bald eagles (BAEA) that are taking foxes? Suggest that this is for future discussion. Comment: on Catalina there are 5 active BAEA nests and no evidence that foxes have ever been taken by these or have been found in nests. - Is 30% mortality of released animals to eagles a good use of foxes? Discussion ensued, but suggested that the location of the mortalities indicates much about how we might proceed with future releases and other adaptive management actions. - When was last eagle-killed fox found? May 30 th. - Why are you doing skunk monitoring? Response that we should attempt to understand as well as possible the dynamics of species that have ecological impacts on IF. - What is status of turkeys? individuals are monitored to observe distribution and behavior. Don t know much more than that. - Has there been discussion of collaring a GOEA if it was ever trapped? Lots of ideas are being discussed, and this might be considered. Status of Santa Rosa Island Foxes Tim Coonan, Channel Islands National Park Abstract In 2006, the wild population of Santa Rosa Island foxes (Urocyon littoralis santarosae) remained at 40 foxes, the minimum number known to be alive (MNKA) determined via transect trapping in fall 2006, and radiotelemetry. Current Kaplan-Meier annual survival is 70% (95%CI = 64-82), though annual survivorship dipped below 50% during a portion of 2006, when 20 radiocollared island foxes died. Five radiocollared foxes died from eagle predation in early 2006, though the last occurred over 15 months ago. A number of mortalities occurred in fall 2006 due to a variety of unrelated factors, which included gall bladder infection, intestinal intussusception, emaciation and wound infection, septicemia, and entrapment in a PVC pipe. Reproduction in the wild, as determined via remote cameras and trapping, was higher than that in captivity. Fourteen wildborn pups were captured in fall 2006, and the number of pups/female was greater in the wild (1.75) than in captivity (0.64). Nine pups were produced in captivity in Nine of 14 paired captive females became pregnant, as determined by ultrasound examination, but 12 of 21 pups seen on ultrasound were lost to neonatal mortality. Five females lost their entire litters. One male was observed on camera consuming two pups. In fall 2007, 8-10 foxes will be released to the wild, leaving (13-14 pairs) in captivity. Captive breeding and release to the wild will continue indefinitely, at least until survival in the wild increases markedly, and wild reproduction outstrips that in captivity. Additional notes - In 2006 the GOEA mortalities were not clustered around the Trap Canyon nest site as was the case last year. 8

9 June, In 2006 annual survival dipped below 50%, but is currently 70%, which is comparable to SCI. No predation-caused mortality on this island in 15 months. - Transect trapping will be conducted in the fall to replace collars and trap wild-born pups. MKNA will be calculated by adding the number caught during trapping with others identified via telemetry. - Continued to note aggression in captivity. 4 pairs were separated, 1 female died in surgery intended to repair a non-life-threatening injury, and one male was injured by a female. One male was observed via video eating both of his pups, although not clear whether they were dead first or killed by him animals will be released this year, and 12 pairs will be retained in captivity. On SRI captive breeding and releases will continue until reproduction in the wild far outstrips that in captivity, and survival in the wild increases. Recovery plan will determine criteria, but given current conditions this will probably continue 5-6 more years. Audience questions/comments - What is the difference between the estimated number in the wild and MKNA? Currently they are not sampling to produce an island-wide estimate. - You suggest that captive breeding will continue until breeding in the wild outweighs that in captivity, but how will that be determined? By the number of pups/pair. Would it be more useful to use the net rate of increase in the wild compared to the net rate in captivity to determine when to quit captive breeding? We could do it that way, but we look at relative contribution of each captive and wild animal. - Question on methods of camera placement: there is currently one/territory but they are also moved around. - Which of the released animals are dying? No detectable pattern. Status of San Miguel Island Foxes Tim Coonan, Channel Islands National Park Abstract In 2006, the wild population of San Miguel Island foxes (Urocyon littoralis littoralis) increased to at least 80 foxes, the minimum number known to be alive (MNKA) determined via transect and grid trapping in fall 2006, and radiotelemetry. Reproduction in spring 2007 likely puts the wild population well above 100 animals, for the first time since Current Kaplan-Meier annual survival is high (92%; 95%CI = ), and the last predation-caused fox mortality occurred over 16 months ago. Reproduction in the wild, as determined via remote cameras and trapping, was also high. Thirty-two wild-born pups were captured in fall 2006, and the number of pups/wild female (2.46) was 5 times that in captivity. Remote camera monitoring of wild pairs indicated that in , both captive-born and wild-born juveniles bred in their first year, unlike in captivity. No pups were produced in captivity in Five of 7 paired females became pregnant, as determined by ultrasound examination, but all 5 females failed to produce a litter, and a total of 8 pups were lost. Because both reproduction and survival in the wild is excellent, and reproduction in captivity is negligible, we will cease captive breeding and release of foxes after releases in In summer 2007, 14 foxes will be released to the wild, leaving 2 older females, considered unreleasable, in captivity. The San Miguel captive breeding program 9

10 Summary Report, Island Fox Working Group Annual Meeting produced 53 pups from , and 48 foxes were released to the wild from The captive breeding program was responsible for the increase in San Miguel Island foxes from a nadir of 15 foxes in 1999 to the current 120+ foxes. Additional notes - It isn t completely clear why SMI is doing so much better than SRI, but could be because it s further away from eagle central on SCI. - Interesting point that a high proportion of the 1-year old females, as well as pairs that have only been together one year, are producing many of the litters, and overall productivity per wild pair = There was 1 mortality in 2006 due to emaciation, possibly resulting from aggression, and other mortalities due to uremic poisoning, various injuries, and 1 trichobezoar. - For monitoring they re using transect trapping, but also experimented last year with small grids, trying to mimic the grid trapping methodologies from the early 90s. Another goal was to develop a trapping scenario that could be implemented by a small island staff. The islandwide density estimate calculated from these grids was 65 foxes, and the total number of animals known on the island was 66. Transect trapping resulted in MKNA of Annual survival on SMI was 20 points higher than on SRI, and is currently at 90%. (80% may be the survival rate needed to maintain a stable population.) There have been no predation mortalities in the past 16 months. - There was no productivity this year in the captive population, even though from ultrasound several females were known to be pregnant. This lead to the conclusion that the captive program is no longer contributing to population recovery. - This year they are planning to release all of the captive animals except 2 unreleasable older females, thus ending the captive breeding program on that island. The facilities will be maintained so they are available if needed. And the point should be made that it was the captive breeding program that got the wild population where it is today. Audience questions/comments - How are you recording aggression-caused injuries to the wild animals, and do you know the causes? Generally we feel that these aggressions are mostly territorial (same-sex), rather than attributable to mate-aggression. In the wild we generally see more wounds in males while in captivity there are more in females. - Is it thought that aggression in the wild is part of their natural behavior or is it something new? i.e. this could simply be consistent with the dynamics of an expanding population as it sorts things out, a condition that will diminish over time. Answer is that this seems reasonable, and most people think that this is probably natural behavior. It was further pointed out that aggression is seen less in established territories, but that released foxes have no experience with territoriality, and just don t know how to deal with each other in these circumstances. 10

11 June, 2007 Mainland Populations Update Alan Varsik, Santa Barbara Zoo In summary, the status of the mainland populations is not great; both the Los Angeles and the Santa Barbara (SB) zoos each lost a female this last year. There are currently 11 San Clemente foxes in captivity, but only one of those is a female. There is also the one Santa Rosa fox (the one with the eye challenge) at the SB zoo. This animal is generally healthy. His role as an education/ambassador animal remains questionable due to his perceived discomfort in bright areas and among larger groups of people. The good news is that a male pup was born at SB zoo this spring and is doing very well. Due to a medical challenge with the dam, this pup was handreared. He has already indicated a significant comfort around staff and may likely become and education/ambassador fox. The larger role of the American Zoo Association (AZA), and zoos in general, in island fox conservation was discussed. 13,000,000 people attend AZA facilities in California annually, so these venues could be an important vehicle for education and communication of island fox issues. Total AZA attendance nationwide is 143,000,000, so there could be even greater opportunities to share the island fox story. These facilities also provide opportunities for research and other animal husbandry and population management resources, and as discussed in the past, could also potentially provide a redundant population for recovery and conservation needs. The focus for AZA zoos is currently on developing a small, but viable, population of San Clemente foxes. Current mainland efforts include creating a Memorandum of Understanding (MOU) between the AZA and CA Fish and Game to transfer additional foxes to zoos from San Clemente. To do this all parties involved would have to agree that losses of animals from the population due to these transfers would not be detrimental. (This subspecies is not federally listed.) These transfers would use existing methodologies and possibly implement the plan as previously discussed by the RCG, which considered taking 5 individuals/year from the island for a period of 5 years. Also, the SB zoo is currently breaking ground on a significant renovation of their IF exhibit, and Alan is working with Cal State Channel Islands to possibly establish an IF breeding facility. He suggests that, overall, there is hopefully a future for island foxes on the mainland, and that long-term conservation of the IF is dependent on an awareness of the conservation issues surrounding long-term recovery, something that zoos certainly have a tremendous ability to generate. Audience questions/comments - What would the timeline be for moving more SCL foxes to the mainland? Hopefully sooner rather than later, because some of these zoos that are down to one animal will likely begin phasing out their programs if they didn t see a future that includes more animals. Comment that the zoo community is still interested, and as long as wild numbers continue to grow that there should be future discussions on bringing animals also from Santa Cruz. - Could there be (are there facilities and/or interest) in having two populations on the mainland (San Clemente and Santa Cruz)? Comment from an RCG member that their idea is that there would eventually be an education population at one or a few zoos, but that if it were decided that there is a need for a captive research population, that a mainland Santa 11

12 Summary Report, Island Fox Working Group Annual Meeting Cruz population could serve both for research and redundancy. So having both of these on the mainland would not necessarily be competitive. - Another comment was made that it is clear from the data that captive breeding problems have not been solved on the islands, and that because the land managers are hoping to close down their island facilities as soon as possible, that there are many existing questions that could be answered by mainland captive populations. - What is the AZA taxonomy advisory group s position on a mainland population? The Regional Collection Plan has identified several small canid spaces that would be available. It has also has been determined that there is probably additional space for about 25 animals in other facilities, but a specific plan is yet to be developed. Some analysis has been done on genetic consequences of various mainland population sizes, and that information could be used for further discussions. - Comment that the IUCN captive breeding specialists group has identified small canids as a priority, and that the IF really fits the bill for several critical small canid issues. Final thought that the AZA is still very interested in IF and is holding some space, but that without new animals fairly soon it isn t clear how long that interest will last. Island Fox Health Issues Linda Munson, UC Davis School of Veterinary Medicine Winston Vickers, Institute for Wildlife Studies Abstract Health surveillance of all 6 subspecies of island fox has been in progress since The principal aim of surveillance has been to determine what diseases occur in island fox populations and to assess the impact of these diseases on mortality and fertility. This comprehensive surveillance includes complete gross and histopathologic exams on all foxes that die, surveillance of pathogen exposure through serology, assessment of parasite burdens, and veterinary exams of captive and wild foxes. Blood tests, cultures, and biopsies of foxes with clinical disease have also been conducted. To date more than 500 necropsies and 140 biopsies representing all six subspecies have been evaluated. From June 2006-May 2007, 107 carcasses were received. A database of health information is being accrued. These data are being analyzed to determine whether diseases differ 1) among subspecies, 2) within a subspecies during times when populations were declining or robust, and 3) before and after the population declines on San Miguel (SMI), Santa Rosa (SRI), Santa Catalina (CAT), and Santa Cruz (SCI). Diseases that are prevalent or appear to affect population viability are further investigated to determine the pathogenesis and risk factors for disease development so that preventive strategies can be implemented if possible. Detailed Summary In , vehicular trauma continued to be a major cause of death on the southern islands. Another cause of death on San Nicolas (SNI) in was severe infestation of Spirocerca with intestinal perforation in aged foxes. Causes of death in San Clemente (SCL) foxes other than trauma included emaciation due to amyloidosis or systemic mineralization. On the northern islands, eagle predation was confirmed in 32 carcasses last year and suspected in others, most of 12

13 June, 2007 which were SCI foxes. Serious fight wounds were the primary or contributing cause of death in several foxes from all islands. In the fall of 2006, a cluster of non-predation mortalities occurred on SRI. Although there was originally a concern that an epidemic was occurring, most of the deaths were determined to be due to disseminated bacterial infections from infected wounds or intestinal and gall bladder infections. Although a variety of diseases are found in island foxes, several diseases are notable for their high prevalence: ceruminous gland carcinomas and severe otitis in CAT foxes; colonic spirocercosis in foxes; systemic amyloidosis; systemic mineralization on SCL, and thyroid disease. Canine distemper virus (CDV), rabies, and canine adenovirus (CAV) are infectious agents of concern due to their potential to cause catastrophic declines in foxes, but only one fox to date has been identified with CDV and no cases of rabies or CAV have been identified. Forty-eight cases of ceruminous gland carcinoma have been identified to date in SCAT foxes; foxes from other islands appear not to be affected. The prevalence in SCAT foxes > 3 yrs old is approximately 40%. These cancers can occlude the ear canal, invade surrounding tissues, and metastasize causing considerable morbidity. Why SCAT foxes have such a high prevalence of this cancer is under investigation. Spirocerca is a parasite that causes large fibrous nodules in the colon. Infected foxes have been found on all islands, but the prevalence ranges from 56% - 71% on SNI, SCI, SRI, and SMI to only 1% on SCL and CAT. Although most cases are subclinical, these parasites can cause rectal prolapse, intestinal blockage, or intestinal perforation. Treatment has not been recommended in subclinical cases, because the treatment may cause more harm than benefit. This spirurid may not be present on the mainland, so transfer of infected animals should be prevented. Many foxes have systemic amyloidosis with deposits of this abnormal protein in the oral cavity, larynx, lungs, hearth, kidneys, liver, spleen, skin, and other organs. These deposits compromise organ function, leading to organ failure and emaciation. The most severe cases have occurred in captive foxes and preliminary risk analysis suggests that captivity is a significant risk factor. The prevalence is higher in SCL foxes. Because most affected foxes do not have the predisposing condition of chronic inflammation, chronic stress and genetic predisposition are suspected. Mineralization of vascular structures and multiple organs has been noted in SCL foxes. Most cases appeared to be subclinical, but mineralization appeared to be a major contributing cause of death in some animals. Exposure to Quintox is suspected.. Thyroid disease is highly prevalent in all fox subspecies. Adult foxes have small thyroids with little hormone storage, and numerous tumors have been noted. Preliminary studies suggest that circulating thyroid hormone concentrations are low. Because adequate thyroid function is essential for general health and reproduction, thyroid atrophy may affect the ability of foxes to remain healthy during times of stress. Further studies evaluating thyroid function and determining if environmental contaminants are associated with this condition (as is true for other species) are recommended. 13

14 Summary Report, Island Fox Working Group Annual Meeting Infectious diseases, such as CDV, CAV and rabies continue to be of concern for the recovering populations. The suspected CDV epidemic on CAT illustrates the impact such diseases can have on small populations. Many foxes have antibodies to a CDV-like virus and only one fatal case has been identified, so a low-pathogenic CDV strain is likely present on the islands. Similarly, foxes on most islands have evidence of exposure to CAV, which is usually highly lethal in foxes, yet no disease has been noted, suggesting a low pathogenic strain. Health concerns for captive animals include amyloidosis, fight wounds, mastitis, and reproductive failure/neonatal deaths. Concerns for moving foxes to the mainland or among islands include parasite infections and stress-induced diseases. Continued disease surveillance is recommended in all populations to detect emerging diseases. Necropsy of all deceased foxes will be continuing, and risk factor analyses for these prevalent diseases will be conducted. Research contributing to the understanding of major health problems of island foxes is ongoing. Continued efforts should be made to better understand causes of reproductive failure and mastitis in captive foxes, and to reduce injuries due to aggression. Vaccination should be utilized to protect the majority of foxes on some islands, and core populations on others, against CDV and rabies. Audience questions/comments: - Is any work being done on skunk diseases? This has been proposed, but right now they can t take on any more work. - Is the proposed risk assessment the same as what was done for distemper? No, this would be across islands and for all major diseases. Reproductive Failure Monitoring: Results and Recommendations Cheryl Asa, St. Louis Zoo Deana Clifford, University of California Davis Winston Vickers, Institute of Wildlife Studies Betsy Calkins, St. Louis Zoo Karen Bauman, St. Louis Zoo Abstract In our second year of monitoring phases of the reproductive process we studied all the Santa Rosa pairs (n=14), but were able to observe and collect fecal samples from only 6 of the 7 San Miguel pairs. However, ultrasound exams, which were conducted on all paired females, showed general agreement with relaxin assays for pregnancy diagnosis, but ultrasound also reveals the number of fetuses and allows estimation of parturition date via fetal measurement. Our results indicate that most losses are occurring in the perinatal period, either as late term abortions, stillbirths, or neonatal deaths. However, insufficient camera coverage in dens prevented distinguishing among these possibilities. For pups that disappeared, males were seen consuming pups in at least two of the cases, but it was not possible to discern whether pups were already dead or were killed by the parents. 14

15 June, 2007 Proportion of Females Observed Mating (Video or Live) San Miguel Santa Rosa (N=7) (N=14) 5 of 6 Review not complete Ovulated 6 of 6 14 (Hormones) Pregnant 4 of 7 9 (Ultrasound) Litters Born (Observation & pup checks) 1 of 7 8 Litters Surviving 0 4 We also are evaluating the potential role of stress, as measured by fecal cortisol levels, in reproductive failure and intra-pair aggression. Results from a female that had very high cortisol while in the "foxpital", with levels falling to apparent baseline after return to her home enclosure, will help us evaluate the aggressive interactions occurring in the pairs, which are rather common and can be initiated by either males or females. Mastitis was detected in fewer females this year, perhaps due to prophylactic antibiotic treatment of all females. Two mastitis deaths occurred in 2005, but none in 2006 or Mastitis cases in captive foxes: Island San Miguel (1 other cultured pathogens, but not clinical; 2 cultured probable contaminants) Santa Rosa 4 1 definite, 2 probable Santa Cruz diagnosed at ultrasound (1 persisted; 2 others cultured pathogens; 1 cultured contaminants and Bordetella) Our recommendations include 1) providing better den camera coverage to determine whether pups are born and, if so, whether they are alive, 2) removing males after ultrasound exams in mid-march, 3) further investigation of diseases potentially associated with perinatal death, and 4) alternative treatments for prevention of mastitis. Additional notes - It appears more and more likely that disease is an important factor in reproductive success. - There are many steps in reproduction where failure can occur, including courtship and mating, ovulation, conception, pregnancy maintenance, parturition, and parental care/health. - The methodologies for the reproductive study were: On SMI, they observed and obtained fecal samples from 6/7 pairs. Three of these females previously bred successfully and all of them were more than 1 year old. The animals were observed from blinds at dawn and dusk, and there was confirmed habituation to observer. Suggests that it was unlikely that observer presence was a factor. On SRI there were 14 pairs under video surveillance. 5 of these were 15

16 Summary Report, Island Fox Working Group Annual Meeting pairs that were observed last year, and the others were either animals that had new mates and/or had changed pens. There were 2 yearling pairs. Cameras were installed in some but not all of the den boxes. Methodologies for ultrasounding were: All breeding females on CAT, SCL, SCI, SRI and SMI underwent ultrasound and physical exams beginning in mid- March. They also conducted some Relaxin assays. - The results of the reproductive study were: On SMI there were 5 confirmed matings, 6 females that ovulated, 4 females that became pregnant, but there were no surviving litters. The females that ovulated likely mated, but they either failed to conceive, or there were abortions during late pregnancy. On SRI 14 females ovulated, 9 became pregnant, 8 litters were produced, and 4 of these survived. 1 pair of yearlings reproduced, and only one newlyformed pair was successful. Pups disappeared (were either stillborn, compromised, or killed by parents) in 4 of the 8 litters. The results of ultrasounding were: The minimum proportion of pregnancies was the same across the islands, but SCI had much higher pup survival than SRI, and there was none on SMI. Even with all of the management changes and pen improvements implemented over the last several years, the proportion of pups surviving to weaning has not increased. Relaxin assays were not always reliable in determining early pregnancies. Discussion - Possible causes of early embryo loss can be either very young or very old mothers (however this doesn t explain the results here), genetically abnormal embryos, poor maternal nutrition, and/or disease. Late pregnancy loss is quite common in many mammals, and can be due to abortion/stillbirth, fetal genetic/development defect or disease, stress (but less likely in late pregnancy), death at parturition, and neonatal death (several causes, including infanticide). Their data cannot eliminate the possibility that all losses are neonatal, but the absence of denning behavior on SMI suggests late-term abortion. Is this a recent development in the captive populations? Could be, but is also true that in the past newborn pups weren t usually observed, so prior rates of neonatal loss are unknown. - Could stress cause embryo loss? Yes, but don t know what true stress is for foxes, and need to have cortisol levels obtained when a fox is know to be really stressed to know this. They attempted HCH stimulation and not much cortisol was released, although the dosage they used was for domestic dogs and may be too low for foxes. They also got cortisol levels from a fox in the foxpital so this might be a good measure for future studies. - There were high levels of aggression across all SRI and SMI pairs, even though they are commonly seen hanging out together, (usually a sign of compatibility in captive animals). But in many cases IF pairs can hang out much of the time, but then have serious aggressive interactions. So maybe simply observations of hanging out behavior don t necessarily indicate domestic bliss in IF. In general, young males produced more detected wounds, and females with detected wounds have lower reproduction. For management, they suggest closer observation of mated pairs, mate change or mate removal if necessary, and additional general husbandry changes such as pen changes and improved nutrition, to possibly reduce aggression. - Mastitis clearly affects pup survival, but it may not always be clinically apparent. There were 2 mastitis deaths in 2005, but none in 2006 or Pen modifications may have helped prevent mastitis. Also in 2006 they used prophylactic antibiotics on those females that had mastitis in 2005, and used them on all females in

17 June, 2007 Summary The good news is that all females are ovulating, and most are conceiving. The bad news is that most pregnancy failures occur after mid-gestation, and we generally can t determine the specific causes (late abortion, stillbirth, and neonatal death). Results from the CAT captive breeding program suggest that the majority of losses were after pups were born. Mate aggression seems common and should be considered an issue affecting reproductive success. They suggest possibly increasing pen spacing to address this problem. Additional recommendations include increasing den cameras, possibly moving males after mating is observed, and further investigation of disease (specifically mastitis) and other factors as influences on reproductive success. Audience questions/comments - Did you get fecal corticoid from wild foxes? Yes, but these data haven t yet been analyzed. - Is perimeter fencing present? Yes on SRI and SMI, but not on SCI because those pens are more spread out. - What is the schedule for the rest of the reproductive study? They are now in the data analysis phase, and data collection is complete. - Comment that it looks like removing males might be something to consider, and response that this is in their recommendations. - Comment that this kind of aggression was not observed on CAT, although there were cases of abandonment. For that program they succeeded in improving pup survival by removing pups soon after birth, suggesting that the benefits of early neo-natal parental care did not outweigh the negative impacts of a bad situation (possible abandonment). - Does pair aggression occur throughout the breeding season? Yes. - What are reproductive rates of mastitis-positive females once they are released? Don t know, and suggest that we should look more closely at this question. Contemporary Evolution in the Santa Cruz Island Fox Hilary M. Swarts, Kevin R. Crooks, Neil Willits, Rosie Woodroffe Abstract There is increasing recognition that species persistence in a human-dominated world may depend on their ability to mount rapid evolutionary responses to environmental change. We present evidence of such possible contemporary evolution in the anti-predator behavior of the critically endangered Island fox (Urocyon littoralis). In 1994, golden eagles colonized Santa Cruz Island, CA and devastated the predator-naïve, endemic island fox population by 95% within 10 years. When studied in 1992, just prior to golden eagle colonization, foxes showed substantial diurnal activity, but diurnal activity was significantly lower in , when golden eagles were present. This was not a result of reduced overall activity, nor was it a density effect, as diurnal activity has remained low even as the Cruz fox population has grown since Moreover, on nearby Santa Catalina Island, where golden eagles were absent but where the fox population recently crashed due to a disease epidemic, remaining foxes were significantly more diurnally active than were those on Santa Cruz Island. This further suggests that the change in activity pattern was a response to predation, not to low population density. The weight of evidence suggests that predation by golden eagles selected against diurnal activity. This 17

18 Summary Report, Island Fox Working Group Annual Meeting behavioral change may allow for prolonged island fox persistence as long as the eagle population is maintained at very low numbers. However, the loss of daytime activity could influence individual fox foraging, mate selection, and territorial defense and might even alter the ecology of the entire island. Ultimately, the improved prognosis for the Cruz fox population s long-term persistence must be regarded cautiously in light of the possible costs to individual fox fitness and potential for wide-reaching effects on the ecology of the island. Additional Notes This study focused on temporal behavior of IF and possible effects on IF circadian activity from golden eagles (GOEA). SCI foxes were highly diurnal prior to the onset of predation by GOEA. GOEA are diurnal hunters, and impacts from predation obviously devastated IF populations. The study questions were: 1) Have SCI foxes reduced their levels of diurnal activity? 2) If so, what might be the causative mechanism(s)? Data were collected on SCI (GOEA present) and CAT (no eagles), from , and compared with historic data from Activity patterns were measured via radiotelemetry, specifically to identify active and inactive individuals and the proportion of animals with diurnal and nocturnal activity. Several independent variables were compared between the 1992 and the data. Results suggest that diurnal activity dropped off significantly when eagles were present. But was this due to direct predation effects, or something else, like a density effect. A description of the analyses was presented. First she looked at densities on CAT and SCI, and overall changes in density against changes in diurnal behavior. Did observe a downward trend by year; SCI animals were 43% less active diurnally than were CAT animals. Density decreased overall, but not as much as animals with diurnal behavior. These results suggest that there was in fact a predation effect on behavior. If this is true, the next question to be addressed is whether changes in behavior were due to evolution or learning. She suggests they have a constrained ability for learning, since their first encounter with an eagle is very likely their last encounter. And there is very little physical evidence that there near misses are common. Also animals are often solitary, so this likely reduces the opportunities for learning (i.e. watching another animal get taken). And there is no apparent anti-predator behavior shown upon eagle arrival; IF are generally fairly tame and not fearful. So, these factors suggest that they wouldn t quickly develop a learned response. There is a genetic basis for circadian activity, and Roemer s data support a serious selection event. He found a correlation between the likelihood of eagle mortality and diurnal activity, and that animals that survived to the end of his study had less diurnal activity. These observations suggest an extremely fast rate of contemporary evolution. This is probably advantageous in terms of conservation, in that if true, there should now be higher rates of survival in the presence of eagles, even with the removal of pigs. There are probably also evolutionary costs, in the there may be reduced fitness with less diurnal activity, and there may further be island-wide repercussions from changes in IF behavior. Audience questions/comments - Are there seasonal differences? Not really, and neither were there individual differences. - Are there any data on the individuals that were killed in the last six months? Those data have not been included in her analysis. 18