Foxes and food subsidies: anthropogenic food use by red and Arctic foxes, and effects on Arctic fox survival, on the Arctic Coastal Plain of Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2013Food subsidies have the potential to impact wildlife on the Arctic Coastal Plain of Alaska. Red foxes (Vulpes vulpes (L., 1758)) expanded their range into Arctic regions during the 20th century, and the availability of anthropogenic foods may have contributed to their success and persistence in the Arctic. Arctic foxes (Vulpes lagopus (L., 1758)) are also known to forage on anthropogenic foods in Prudhoe Bay and to forage on marine mammals on the sea ice, but it is unknown whether these strategies benefit survival of Arctic foxes. This thesis examined: 1) the importance of anthropogenic foods to the diets of red and Arctic foxes in Prudhoe Bay, and 2) the factors with the greatest effect on Arctic fox survival, including access to food subsidies in Prudhoe Bay and on the sea ice. For the first study, stable isotopes of red and Arctic fox tissues were used to infer late summer, late winter, and lifetime (for red fox only) diets. The contribution of anthropogenic foods to the diets of both species was low in late summer (~10%) but high in late winter (49%, 95% credible interval = 38-57%, of red fox diets and 37%, 95% credible interval = 29-44%, of Arctic fox diets). Estimates of lifetime diet in red foxes revealed high levels of anthropogenic food use, similar to the winter diet. To characterize the extent of competition for food resources, dietary niche overlap was examined between both species by comparing isotopic niche space. Both fox species had little isotopic niche overlap but may have greater overlap between their ecological dietary niches. Availability and consumption of anthropogenic foods by red foxes, particularly in winter, may partially explain their year-round presence in Prudhoe Bay. For the second study, nest survival models and satellite collar data were used to evaluate whether multiple factors affected survival of adult and juvenile foxes. Site and sea ice use had two times more support than the other factors. Three groups of foxes were identified based on capture location and sea ice use, which corresponded to different survival rates: Prudhoe Bay foxes, NPR-A foxes that used sea ice during more than eight 2-week periods during the winter (seven 2-week periods for juveniles), and NPR-A foxes that did not use sea ice. Both adult and juvenile foxes at Prudhoe Bay had modestly higher annual survival rates, 0.50 (90% CI 0.31-0.69) and 0.04 (90% CI 0.0-0.08) respectively, than foxes at NPR-A that did not use sea ice, 0.40 (90% CI 0.18-0.62) and 0.01 (90% CI 0.0-0.04) respectively. NPR-A foxes that used sea ice extensively had the highest survival rates. Food subsidies may have far-reaching effects on red and arctic foxes on the Arctic Coastal Plain of Alaska

Multi-population comparison of resource exploitation by island foxes: implications for conservation

Imperiled island foxes are inherently resource-limited by their insular ecology. We examined food use on all 6 islands where they occur to assess resource exploitation patterns. Over 40 different food items were identified with item use varying among islands. Sixteen items occurred with ≥10% frequency in annual fox diets: deer mice, birds, lizards, beetles, beetle larvae, Jerusalem crickets, silk-spinning sand crickets, grasshoppers, earwigs, snails, and fruits of toyon, manzanita, prickly pear cactus, ice plant, Australian saltbush, and summer holly. Foxes used a diversity of food items with variations among islands attributable to island-specific availabilities. Deer mice in particular appeared to be preferred. Foxes also exhibited extensive use of non-native items, such as ice plant fruits, European snails, and earwigs, and foxes may even be dependent on these items on some islands. To increase food security and promote population stability, we recommend (1) continuing and enhancing habitat restoration efforts on all islands, (2) increasing the abundance of native items in association with any removals of non-native species used by foxes, and (3) monitoring annual trends in abundance of key food items as well as periodic monitoring of item use by foxes to determine functional responses to changes in item availability

Echinococcus multilocularis: An emerging pathogen in Hungary and Central Eastern Europe?

Echinococcus multilocularis, the causative agent of human alveolar echinococcosis, is reported for the first time in Red Foxes (Vulpes vulpes) in Hungary. This parasite may be spreading eastward because the population of foxes has increased as a consequence of human interventions, and this spread may result in the emergence of alveolar echinococcosis in Central Eastern Europe

Detection of Leishmania DNA in wild foxes and associated ticks in Patagonia, Argentina, 2000 km south of its known distribution area

Indexación: Web of Science; PubMedBackground: Zoonotic Visceral Leishmaniasis (ZVL) is a vector-borne disease affecting humans and other mammals and caused by the protozoan parasite Leishmania (Leishmania) infantum (syn. L. chagasi), belonging to the L. donovani complex. The regions in Northern Argentina (above 32 degrees S) are its southern distribution limit in South America. Results: We detected Leishmania sp. DNA (most likely belonging to the L. donovani complex) in 37.5 % of 32 grey foxes (Pseudalopex griseus) captured in Argentinean Patagonia (48 degrees S and 50 degrees S). Eleven monosexual pools of Amblyomma tigrinum ticks from eight different foxes (six grey foxes and two culpeo foxes P. culpaeus) were also positive. The southernmost known distribution limit for L. infantum, and the southernmost reported capture of a phlebotominae, had previously been 2000 and 750 km north of our study area, respectively. Conclusions: This finding is significant because it markedly extends the distribution area of leishmaniasis; supports the existence of a sylvatic cycle in the absence of dogs; and has implications in transmission, indicating that either sand fly distribution is broader than currently thought or non-sand fly Leishmania maintenance is possible. Additional molecular, parasitological, epidemiological and entomological studies are still needed.http://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-016-1515-

The relationship between humans and urban foxes on Prince Edward Island

This study examines the relationship between humans and urban foxes living in Charlottetown, Prince Edward Island. In recent years colloquial evidence suggests that there has been an increase in foxes living in urban areas of Prince Edward Island, which may eventually lead to an increase in negative interactions. An online questionnaire was administered to 456 residents of Prince Edward Island, in order to explore their attitudes and interactions towards foxes. The survey results were examined using thematic analysis in order to identify common attitudes towards foxes in residents of Charlottetown. The themes identified were: positive attitudes towards urban foxes, negative attitudes towards urban foxes, concern for the safety of foxes, concern for the safety of humans, concern about loss of wildlife habitat, and concerns about humans feeding foxes. Our findings showed that most respondents on Prince Edward Island have positive attitudes and feelings towards foxes. In order to explore the relationship between humans and urban foxes, the histories of foxes in England and Prince Edward Island were documented and compared. Foxes began entering urban areas in England during the 1940s, and were initially received well. Due to a large population of bold urban foxes, as well as outbreaks of disease in the fox population, foxes are now less welcome in urban areas of England. By comparing human attitudes regarding foxes between Prince Edward Island and England, we hope to obtain insights into future attitudes towards foxes on Prince Edward Island

Microsatellite loci among Alaskan rabies hosts: Arctic and red fox

Little is known about the population dynamics between Arctic and red foxes in Alaska and consequences for rabies ecology. Both species carry different variants of rabies and inhabit different environments. As the global warming trends progress, the Arctic and red fox will have increased habitat overlap due to northward range expansion of the red fox into the historic habitat of the Arctic fox. Hypothesis: global warming trends will significantly influence the disease dynamics between red and Arctic foxes as well as their roles in disease dynamics in the far North. In order to better survey the movement of the variants of rabies among Arctic and red fox, microsatellites will be used to assess population structure of these host species

Comments on Estimating Population Rate of Increase from Age Frequency Data

Although many papers have described assumptions and calculations of r from different kinds of data, none has compared estimates of r for the same real data set under different assumptions. We used the age distributions of gray foxes collected during six trapping seasons to estimate and compare r and lₓ series derived under different assumptions. Because trapped foxes are killed, they are believed by some to represent death history data. We found this treatment underestimates mortality so overestimates survivorship and leads to erroneous conclusions about the population. Use of a projection matrix allowed prediction of population size and thus allowed us to predict observed rate of increase. Use of projection matrices also resulted in the most conservative estimated of r

The Ecology of Red Foxes, Vulpes vulpes, in Metropolitan Toronto, Ontario: Disease Management Implications

During 1989-1992, 33 Red Foxes (Vulpes vulpes) were fitted with radio-collars in metropolitan Toronto to study their behaviour which would provide data to assist with the design of a rabies control strategy for urban areas of Ontario. Annual home range size for adult foxes (avg = 325 ha, SD = 207) was significantly larger than that of juvenile foxes (avg = 165 ha, SD = 176), but we could not detect any seasonal differences in home range size for foxes. Mean (SD) nightly ranges were 38.3 ha (48.3) in spring, 97.4 ha (115.4) in summer, 26.8 ha (28.5) in fall, and 16.3 ha (13.6) in winter. Movements by foxes during the period from June to November averaged 3.5 km (2.89). Eleven of the foxes were known to have dispersed (? 3 km from their home range), but we could not detect a mean direction of dispersal. Thirty-six percent (4/11) of the foxes dispersed in December and 18% (2/11) dispersed in August, with the remainder dispersing between February and November. Average dispersal distance was 19.3 km (15.6), and a significant negative correlation was detected between initial home range size and dispersal distance of foxes. Mortality of radio-collared foxes was caused by collisions with automobiles, predation, and shooting. Foxes made extensive use of ravines and other greenbelt areas, such as parks and golf courses. Residential areas were also used by some foxes. Knowledge of the habitats frequented by foxes as well as their movement potential assisted researchers in determining where vaccine baits should be placed for the control of rabies in Red Foxes in metropolitan Toronto

The Food Habits of the Red Fox and Gray Fox in Louisiana with Notes on Reproduction and Parasitism

Stomach contents of 54 red foxes ( Vulpes vulpes) and 20 gray foxes (Urocyon cinereoargenteus) were examined to detennine food habits, In both species, rodents, rabbits (Sylvilagus sp .), insects, and blackberries (Rubus sp.) were the most frequently occurring foods. There were no cases of predation on iame birds other than 1 Canada Goose (Branta canadensis) found in a red fox from Cameron Parish. Only 1 occurrence of predation on domestic chicken (Gallus gallus) and 2 occurrences of predation on domestic goat (Capra hircus) were noted. The reproductive condition of females of both species was examined. The average number of placental scars in 19 female red foxes was 5,J and ranged from 2 to 8. The average number of placental scars in 7 female gray foxes was 3,9 and ranged from 2 to 7, Ages of 23 red foxes ranged from 1 to 4 years based on cementum annuli counts. The average age was 1,53 years. Only 4 gray foxes, 3 that were 1 year old and 1 that was J years old, were aged. Heartwonns (Dirofilaria immitis) were found in 5 of Jl red foxes and 2 of 20 gray foxes, Stomach worms (Physaloptera sp.) were present in 4 red foxes and 1 gray fo

Island Fox Spatial Ecology and Implications for Management of Disease

Disease, predation, and genetic isolation resulted in 4 of 6 island fox (Urocyon littoralis) subspecies being listed as endangered in 2004. Potential for disease outbreaks continues to pose a major threat to the persistence of these isolated, endemic populations. We examined how roads influence the spatial ecology of San Clemente Island foxes (U. l. clementae), particularly in regard to spread of disease, to provide management recommendations for preventing or minimizing a disease outbreak on San Clemente Island, California, USA. Home range areas (x=0.75 km2) and core areas (x=0.19 km2) of foxes on San Clemente Island were 0.36–1.23 and 2.17 times larger, respectively, than estimates from Santa Cruz Island foxes (U. l. santacruzae). Home ranges and core areas were 78% larger and 73% larger, respectively, for foxes near roads than for foxes away from roads. Home ranges were also largest when foxes were not caring for offspring (i.e., seasons of pup-independence and breeding). We did not detect any dispersal movements, but foxes living near roads moved 33% farther in 2-hour periods than foxes not living near roads. Foxes near roads move faster, range more widely, and could more rapidly spread a pathogen throughout the island; therefore, roads might serve as transmission corridors.We recommend reducing this risk by increasing widths of vaccination firewalls (areas where vaccination is used to induce a disease-resistant or immune population of foxes), ensuring these areas deliberately intersect roads, and vaccinating a higher proportion of foxes living near roads. Disease risk models incorporating these strategies could inform the lowest risk scenarios