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Context: Feral cats, Felis catus, have caused the decline and extinction of many species worldwide, particularly on islands and in Australia where native species are generally naïve to the threat of this introduced predator. Effectively reducing cat populations to protect wildlife is challenging because cats have a cryptic nature, high reproductive rate and strong reinvasion ability. Aims: We experimentally tested the response of feral cats and their native prey to an Eradicat® poison baiting program at a conservation reserve. Methods: Baits were distributed by hand along roads and tracks every 50 m (∼10 baits km-2). We used camera traps to monitor the response of cats to baiting using a repeated before-after, control-impact design over 6 years. We also measured introduced rabbit, Oryctolagus cuniculus, activity by using sand pads and small mammal and reptile captures by using pitfall trapping. Key results: Dynamic occupancy modelling showed only modest effects of baiting on cats in 2 of 6 years, with occupancy in the baited area decreasing from 54% to 19% in 2014 (-35%) and from 89% to 63% in 2017 (-26%). Baiting effectiveness was not related to antecedent rainfall or prey availability. Bait availability was reduced by non-target interference; 73% of 41 monitored baits were removed by non-target species. We found no evidence for persistent changes in small mammal or reptile capture rates in the baited area relative to the unbaited area over the life of the project. Conclusions: Relatively low baiting density and non-target interference with baits are likely to have reduced baiting efficacy. Further testing and refinement of ground baiting is needed, including trialling higher baiting densities and/or frequencies. Implications: We highlight key areas for future research that should benefit feral cat management not only in Australia, but also on the many islands worldwide where cats threaten native wildlife.

U periodu od 2015. do 2018. godine ispitane su 223 lisice i 64 šakala sa područja Vojvodine Parazitološkim pregledom konstatovano je prisustvo 9 vrsta crevnih helminata, od toga jedna vrsta metilja (Alaria alata), četiri vrste pantljičara (Mesocestoides spp., Ecinococcus multilocularis, Taenia pisiformis, Taenia hydatigena) i četiri vrste nematoda (Toxocara canis, Toxascaris leonina, Uncinaria stenocephala, Pterygodermatites affinis). Nematoda Pterygodermatites affinis je prvi put zabeležena u Vojvodini. Izolovane su 4483 jedinke parazita, od toga 3826 kod lisica i 657 kod šakala. Zabeležena je veća zaraženost lisica (79.8%) u odnosu na šakale (57.8%) (p=0.0003). Najveći procenat obe vrste domaćina (Vulpes vulpes - 49.3%; Canis aureus - 42.2%) bio je zaražen pantljičarama roda Mesocestoides. Kod obe vrste domaćina, vrednosti Berger-Parkerovog indeksa ukazale su na relativno ujednačenu respodelu parazita po vrstama u ukupnom uzorku, dok su sva tri indeksa (Šenonov, Simpsonov i Berger-Parkerov) pokazala su da je područje Bačke sa najvišim biodiverzitetom zajednica helminata. Za vrste Echinococcus multilocularis i Alaria alata utvrđena je statistički značajna razlika u procentu inficiranih lisica u zavisnosti od područja Vojvodine. Prema taksonomskoj strukturi helmintofaune kod lisica je dokazana najveća procentualna zastupljenost mešovite infekcije (61%), dok se broj vrsta po domaćinu kretao od 1 do 5. Registrovane su 42 različite kombinacije vrsta parazita. Kod šakala se takođe najčešće javljala mešovita infekcija (59%), dok se broj vrsta po domaćinu kretao od 1 do 4. Registrovano je 11 kombinacija crevnih parazita. Koprološki test se u ovom istraživanju pokazao kao nisko osetljiv i manje specifičan za identifikaciju parazita u odnosu na direktan pregled intestinuma nakon autopsije životinje. Prevalenca infestiranih lisica (56.3%) i šakala (48%) dokazana koprološkom metodom manja je u odnosu na prevalencu prema patološkom nalazu. Kod obe vrste domaćina nij, During the period from 2015. to 2018. year, 223 red foxes and 64 jackals from the area of Vojvodina were examined. Parasitological examination revealed 9 species of intestinal helminths, thereof one species of fluke (Alaria alata), four species of tapeworms (Mesocestoides spp., Ecinococcus multilocularis, Taeniapisiformis, Taenia hydatigena) and four species of nematodes (Toxocara canis, Toxascaris leonina, Uncinaria stenocephala, Pterygodermatites affinis). The nematode Pterygodermatites affinis was recorded in Vojvodina for the first time. There were isolated 4483 individuals of the parasite, thereof 3826 at red foxes and 657 at jackals. The higher infestation of foxes (79.8%) compared to jackales (57.8%) (p=0.0003) was recorded. The highest percentage of both hostspecies (Vulpes vulpes- 49.3%; Canis aureus- 42.2%) was infected with tapeworms of the genus Mesocestoides. In both host species, the value of the Berger-Parker index indicated a relatively uniform distribution of parasites by species in the total sample, while all three indices (Shannon, Simpson and BergerParker) showed that the area of Bačka had the highest biodiversity of helminth community. For the species Echinococcus multilocularis and Alaria alata was confirmed a statistically significant difference in the percentage of infected foxes depending on the area of Vojvodina. According to the taxonomic structure of helminth fauna, in foxes was proven the highest percentage of mixed infection (61%), while the number of species per host ranged from 1 to 5. There were registered 12 different combinations of parasite species. In jackals, the mixed infection was also the most common (59%), while the number of species per host ranged from 1 to 4. There were also registered 11 combinations of intestinal parasites. The coprologic test in this study proved to be low sensitiv and less specific for identificatio

Purpose: This study aimed to determine the presence of C. plica in red foxes and to point out the possibilities of different diagnostic methods, that could be used for diagnosis of urinary capillariosis in domestic carnivores. Methods: Seventeen red foxes from hunting grounds in the Kolubara District, Republic of Serbia, were examined in February 2019. Animals to be shot were selected based on the criteria of gamekeepers and the permission of the competent Ministry. After hunting, the foxes were examined by ultrasound and autopsied. After the necropsy, biochemical and sediment analysis of urine morphological identification of isolated adult parasites, and macroscopic/microscopic examination of the urinary bladder and kidney tissue were performed. Results: Adults of C. plica were detected in 3/17 foxes (17.6%) by ultrasound imaging and in 6/17 foxes (35.3%) by necropsy examination. Parasite eggs were found in the urinary sediment of 9/17 foxes (52.9%). The predominant histopathologic changes were amyloid degeneration of the renal glomeruli and proximal tubules (8/17 foxes-47%) as well as acute cystitis (7/17 foxes-41.2%). The occurrence of C. plica was determined in 12/17 (70.6%) of the examined foxes. Discussion: This study is the first record of the C. plica in red foxes in the Republic of Serbia. Diagnostic methods used in this study could make possible the early revealing of capillariosis in domestic carnivores and could provide reliable clinical and parasitological screening of suspect animals. Conclusion: The study presents the first report of urinary capillariosis in a fox population in Serbia. The established high prevalence of C. plica in foxes could presume its higher prevalence in domestic and wild carnivores in the future.

Purpose: This study aimed to determine the presence of C. plica in red foxes and to point out the possibilities of different diagnostic methods, that could be used for diagnosis of urinary capillariosis in domestic carnivores. Methods: Seventeen red foxes from hunting grounds in the Kolubara District, Republic of Serbia, were examined in February 2019. Animals to be shot were selected based on the criteria of gamekeepers and the permission of the competent Ministry. After hunting, the foxes were examined by ultrasound and autopsied. After the necropsy, biochemical and sediment analysis of urine morphological identification of isolated adult parasites, and macroscopic/microscopic examination of the urinary bladder and kidney tissue were performed. Results: Adults of C. plica were detected in 3/17 foxes (17.6%) by ultrasound imaging and in 6/17 foxes (35.3%) by necropsy examination. Parasite eggs were found in the urinary sediment of 9/17 foxes (52.9%). The predominant histopathologic changes were amyloid degeneration of the renal glomeruli and proximal tubules (8/17 foxes-47%) as well as acute cystitis (7/17 foxes-41.2%). The occurrence of C. plica was determined in 12/17 (70.6%) of the examined foxes. Discussion: This study is the first record of the C. plica in red foxes in the Republic of Serbia. Diagnostic methods used in this study could make possible the early revealing of capillariosis in domestic carnivores and could provide reliable clinical and parasitological screening of suspect animals. Conclusion: The study presents the first report of urinary capillariosis in a fox population in Serbia. The established high prevalence of C. plica in foxes could presume its higher prevalence in domestic and wild carnivores in the future.

The cardiopulmonary nematodes Angiostrongylus vasorum, Crenosoma vulpis, Capillaria aerophila and Aelurostrongylus abstrusus, are a cause of concern in the scientific and veterinary community, potentially causing significant disease in domestic animals. To investigate the potential of wild carnivores as reservoir hosts to these parasites, a total of 1041 animals from seven regions of Denmark were sampled: 476 raccoon dogs (Nyctereutes procyonoides), 367 red foxes (Vulpes vulpes), 123 American mink (Neovison vison), 31 beech martens (Martes foina), 30 Eurasian otters (Lutra lutra) and 14 polecats (Mustela putorius). Hearts and lungs were collected and examined for cardiopulmonary parasites. Capillaria aerophila was identified using morphology, whereas A. vasorum and C. vulpis were identified by a duplex real-time PCR, and A. abstrusus by conventional PCR. This is the first Danish report of A. vasorum and C. vulpis infections in raccoon dogs, mink and polecats, and of C. aerophila in raccoon dogs and beech martens. In addition, this is the first time A. vasorum and C. vulpis have been identified in wild animals from the island of Bornholm, just as it is the first report of C. vulpis in American mink, and C. vulpis and A. vasorum in polecats in Europe. The prevalence of A. vasorum appears to have increased in red foxes in Denmark compared to previous studies, while C. vulpis and C. aerophila prevalences are lower. Our data show that several wild carnivores can serve as reservoir hosts for A. vasorum, C. vulpis and C. aerophila in Denmark, and that A. vasorum appears more abundant than previously reported. It is speculated that the A. vasorum increase might relate to increased snail abundance, which may be due to a rise in mean yearly temperatures in Denmark.

The cardiopulmonary nematodes Angiostrongylus vasorum, Crenosoma vulpis, Capillaria aerophila and Aelurostrongylus abstrusus, are a cause of concern in the scientific and veterinary community, potentially causing significant disease in domestic animals. To investigate the potential of wild carnivores as reservoir hosts to these parasites, a total of 1041 animals from seven regions of Denmark were sampled: 476 raccoon dogs (Nyctereutes procyonoides), 367 red foxes (Vulpes vulpes), 123 American mink (Neovison vison), 31 beech martens (Martes foina), 30 Eurasian otters (Lutra lutra) and 14 polecats (Mustela putorius). Hearts and lungs were collected and examined for cardiopulmonary parasites. Capillaria aerophila was identified using morphology, whereas A. vasorum and C. vulpis were identified by a duplex real-time PCR, and A. abstrusus by conventional PCR. This is the first Danish report of A. vasorum and C. vulpis infections in raccoon dogs, mink and polecats, and of C. aerophila in raccoon dogs and beech martens. In addition, this is the first time A. vasorum and C. vulpis have been identified in wild animals from the island of Bornholm, just as it is the first report of C. vulpis in American mink, and C. vulpis and A. vasorum in polecats in Europe. The prevalence of A. vasorum appears to have increased in red foxes in Denmark compared to previous studies, while C. vulpis and C. aerophila prevalences are lower. Our data show that several wild carnivores can serve as reservoir hosts for A. vasorum, C. vulpis and C. aerophila in Denmark, and that A. vasorum appears more abundant than previously reported. It is speculated that the A. vasorum increase might relate to increased snail abundance, which may be due to a rise in mean yearly temperatures in Denmark.

The cardiopulmonary nematodes Angiostrongylus vasorum, Crenosoma vulpis, Capillaria aerophila and Aelurostrongylus abstrusus, are a cause of concern in the scientific and veterinary community, potentially causing significant disease in domestic animals. To investigate the potential of wild carnivores as reservoir hosts to these parasites, a total of 1041 animals from seven regions of Denmark were sampled: 476 raccoon dogs (Nyctereutes procyonoides), 367 red foxes (Vulpes vulpes), 123 American mink (Neovison vison), 31 beech martens (Martes foina), 30 Eurasian otters (Lutra lutra) and 14 polecats (Mustela putorius). Hearts and lungs were collected and examined for cardiopulmonary parasites. Capillaria aerophila was identified using morphology, whereas A. vasorum and C. vulpis were identified by a duplex real-time PCR, and A. abstrusus by conventional PCR. This is the first Danish report of A. vasorum and C. vulpis infections in raccoon dogs, mink and polecats, and of C. aerophila in raccoon dogs and beech martens. In addition, this is the first time A. vasorum and C. vulpis have been identified in wild animals from the island of Bornholm, just as it is the first report of C. vulpis in American mink, and C. vulpis and A. vasorum in polecats in Europe. The prevalence of A. vasorum appears to have increased in red foxes in Denmark compared to previous studies, while C. vulpis and C. aerophila prevalences are lower. Our data show that several wild carnivores can serve as reservoir hosts for A. vasorum, C. vulpis and C. aerophila in Denmark, and that A. vasorum appears more abundant than previously reported. It is speculated that the A. vasorum increase might relate to increased snail abundance, which may be due to a rise in mean yearly temperatures in Denmark.

Piroplasmosis is caused by several species of protozoa such as the Babesia microti-like piroplasm (Bml), an emerging blood protozoan also known as Theileria annae or Babesia vulpes. Infection by Bml was first reported in dogs in Spain where it is endemic today. Recently, a high prevalence of Bml has been increasingly detected in red foxes (Vulpes vulpes) in European countries. The objective of this study was to determine infection levels of this parasite in foxes from Galicia, NW Spain, and ticks species infestation in these carnivores, where they are so far unknown. Samples of blood, spleen and ticks (if present) were taken from 237 hunted red foxes in the Galicia region. Blood smears were prepared for direct parasite observation, and spleen and tick samples were examined by nested PCR. Prevalences of Bml infection in Galician red foxes were estimated at 72% (171/237) by PCR and 38.23% (26/68) by direct observation. Among 837 ticks collected, the main tick identified was Ixodes hexagonus (present in 82.4% of the foxes) followed by Ixodes ricinus (12.3%), Dermacentor reticulatus (12.3%) and Rhipicephalus sanguineus sensu lato (3.5%). From 34 foxes testing positive for Bml, 616 ticks were collected: positive Bml PCR results were obtained in 55.6% (227/408) of ticks collected from 9 foxes, while the 208 ticks from the remaining 25 infected foxes returned negative PCR results. Given that canine piroplasmosis is endemic in this area, our observations point to the red fox as the main reservoir for Bml infection and the high proportion of I. hexagonus among ticks collected from red foxes suggests its likely role as vectors of B. microti-like piroplasm in this region. Further studies are needed for a better understanding of the link between the wild and domestic life cycles of this piroplasm

Angiostrongylosis caused by Angiostrongylus vasorum is an emerging disease in Europe and the red fox (Vulpes vulpes) is considered as a main reservoir species for this parasite. Since there have been no reports of A. vasorum in red foxes in Serbia at the time of carrying out our investigations, the aim of the investigations was to explore the role of red foxes in South Banat (northern Serbia) as reservoirs for A. vasorum. Legally hunted foxes were autopsied in the Veterinary Specialised Institute "Pancevo". The heart, lungs and pulmonary artery were examined macroscopically for evidence of gross lesions and for the presence of adult specimens of A. vasorum. Impression smears of the changed lung tissue were examined microscopically for the presence of first stage larvae of A. vasorum and histopathological examination was performed on lung samples. Out of 24 examined foxes hunted in different locations, 13 had lesions manifested in the lungs, which were suspected to be indicative of angiostrongylosis. In the majority of the foxes distal parts of the pulmonary lobes were swollen, firm, and discoloured to dark-red, dark-yellow and dark-brown. The characteristic lesions in distal parts of the pulmonary lobes were completely consistent with the presence of adult parasites in the right heart and pulmonary arteries, and with the presence of the first stage larvae in the impresion smears. The present finding contributes to the knowledge of geographic distribution of angiostrongylosis in red foxes in Europe and provides valuable information that should raise awareness in veterinarians to consider this parasitosis in dogs with signs of cardiopulmonary diseases.

Wild canides have a high epizootiological - epidemiological significance, considering that they are hosts for some parasites which spread vector born diseases. Increased frequency of certain interactions between domestic and wild canides increases the risk of occurrence, spreading and maintaining the infection of parasitic etiology in domestic canides. The research was conducted in 232 wild canides (172 red foxes and 60 golden jackals). The examined material was sampled from foxes and jackals, which were hunted down between 2010 and 2014, from 8 epizootiological areas of Serbia (North-Backa, West-Backa, Southern-Banat, Moravicki, Zlatiborski, Raski, Rasinski and Zajecarski district). On completing the parasitological dissection and the coprological diagnostics, in wild canides protozoa from the genus Isospora were identified, 3 species of trematoda (Alaria alata, Pseudamphistomum truncatum and Metagonimus yokogawai), cestods from the genus Taenia and 5 species of nematodes (Toxocara canis, Ancylostomatidae, Trichuris vulpis and Capillaria aerophila). The finding of M. yokogawai in golden jackals were, to the best of our knowledge, one of the first diagnosed cases of metagonimosis in golden jackals in Serbia. The continued monitoring of the parasitic fauna of wild canides is needed to establish the widespread of the zoonoses in different regions of Serbia, because they present the reservoirs and/or sources of these infections.

Wild canides have a high epizootiological - epidemiological significance, considering that they are hosts for some parasites which spread vector born diseases. Increased frequency of certain interactions between domestic and wild canides increases the risk of occurrence, spreading and maintaining the infection of parasitic etiology in domestic canides. The research was conducted in 232 wild canides (172 red foxes and 60 golden jackals). The examined material was sampled from foxes and jackals, which were hunted down between 2010 and 2014, from 8 epizootiological areas of Serbia (North-Backa, West-Backa, Southern-Banat, Moravicki, Zlatiborski, Raski, Rasinski and Zajecarski district). On completing the parasitological dissection and the coprological diagnostics, in wild canides protozoa from the genus Isospora were identified, 3 species of trematoda (Alaria alata, Pseudamphistomum truncatum and Metagonimus yokogawai), cestods from the genus Taenia and 5 species of nematodes (Toxocara canis, Ancylostomatidae, Trichuris vulpis and Capillaria aerophila). The finding of M. yokogawai in golden jackals were, to the best of our knowledge, one of the first diagnosed cases of metagonimosis in golden jackals in Serbia. The continued monitoring of the parasitic fauna of wild canides is needed to establish the widespread of the zoonoses in different regions of Serbia, because they present the reservoirs and/or sources of these infections.

Wild canides have a high epizootiological - epidemiological significance, considering that they are hosts for some parasites which spread vector born diseases. Increased frequency of certain interactions between domestic and wild canides increases the risk of occurrence, spreading and maintaining the infection of parasitic etiology in domestic canides. The research was conducted in 232 wild canides (172 red foxes and 60 golden jackals). The examined material was sampled from foxes and jackals, which were hunted down between 2010 and 2014, from 8 epizootiological areas of Serbia (North-Backa, West-Backa, Southern-Banat, Moravicki, Zlatiborski, Raski, Rasinski and Zajecarski district). On completing the parasitological dissection and the coprological diagnostics, in wild canides protozoa from the genus Isospora were identified, 3 species of trematoda (Alaria alata, Pseudamphistomum truncatum and Metagonimus yokogawai), cestods from the genus Taenia and 5 species of nematodes (Toxocara canis, Ancylostomatidae, Trichuris vulpis and Capillaria aerophila). The finding of M. yokogawai in golden jackals were, to the best of our knowledge, one of the first diagnosed cases of metagonimosis in golden jackals in Serbia. The continued monitoring of the parasitic fauna of wild canides is needed to establish the widespread of the zoonoses in different regions of Serbia, because they present the reservoirs and/or sources of these infections.

During the past decade, golden jackal populations have substantially increased, yet little is known of their potential for transmitting parasites within animal and human hosts. In the present study, between 2005 and 2010, 447 jackals from six localities in Serbia were examined for intestinal parasites. Two species of trematodes (Alaria alata, Pseudamphistomum truncatum), three nematodes (Toxocara canis, Ancylostoma caninum, Gongylonema sp.), and seven cestodes (Taenia pisiformis, Taenia hydatigena, Multiceps multiceps, Multiceps serialis, Mesocestoides lineatus, Mesocestoides litteratus, Dipylidium caninum) were identified. Pseudamphistomum truncatum and M. serialis species were recorded for the first time. The overall prevalence of parasitic infection was 10.3%. No significant differences were found in the prevalence of infection between males and females (P > 0.817), between localities (P > 0.502), or with regard to annual cycles (P > 0.502). In the infected jackal population, 65% harboured multiple infections and one individual was a host to five different types of parasite species, the highest number of parasites we recorded in a single host. These findings indicate that although the prevalence of gastrointestinal helminths in the jackal population in Serbia is significantly lower than expected from earlier studies, further monitoring is required given the jackal's rapid population increase.

Predation and fire shape the structure and function of ecosystems globally. However, studies exploring interactions between these two processes are rare, especially at large spatial scales. This knowledge gap is significant not only for ecological theory, but also in an applied context, because it limits the ability of landscape managers to predict the outcomes of manipulating fire and predators. We examined the influence of fire on the occurrence of an introduced and widespread mesopredator, the red fox (Vulpes vulpes), in semi-arid Australia. We used two extensive and complimentary datasets collected at two spatial scales. At the landscape-scale, we surveyed red foxes using sand-plots within 28 study landscapes - which incorporated variation in the diversity and proportional extent of fire-age classes - located across a 104 000 km2 study area. At the site-scale, we surveyed red foxes using camera traps at 108 sites stratified along a century-long post-fire chronosequence (0-105 years) within a 6630 km2 study area. Red foxes were widespread both at the landscape and site-scale. Fire did not influence fox distribution at either spatial scale, nor did other environmental variables that we measured. Our results show that red foxes exploit a broad range of environmental conditions within semi-arid Australia. The presence of red foxes throughout much of the landscape is likely to have significant implications for native fauna, particularly in recently burnt habitats where reduced cover may increase prey species' predation risk.

1. Spatial relationships between Iberian lynx and other carnivores were studied by radio-tracking and/or track censusing in two adjacent areas of Donana (south-western Spain). 2. Both radio-tracking and track censusing showed that lynx were restricted to an undisturbed area of Pistacia lentiscus shrubs called Matasgordas. Minimum and maximum lynx density in Matasgordas were estimated as 0.55 and 0.75 ind. km-2. 3. Egyptian mongoose tracks were mainly detected outside Matasgordas (83% of tracks), European badger tracks were detected most often inside Matasgordas (76% of tracks), and red fox tracks were frequently detected both outside (54%) and inside (46%) Matasgordas. Surveys of tracks and faeces undertaken in other 14 areas where P. lentiscus shrubs also dominated corroborated the census data obtained inside and outside Matasgordas. 4. Trapping and radio-tracking of mongooses and common genets indicated that both species avoided use of Matasgordas. They were almost exclusively trapped (24 out of 25 mongooses and all of 11 genets) and mainly radio-located (94.5% and 95.4% of times, for mongooses and genets, respectively) in the areas of P. lentiscus shrubs situated outside Matasgordas. Their densities were estimated as 0.2 and 0.03 ind. km-2 inside, and as 2.0 and 0.7 ind. km-2 outside Matasgordas for mongooses and genets, respectively. 5. Lynx may kill mongooses, genets, and foxes; thus, the avoidance of Matasgordas by smaller carnivores (mongooses and genets) could be related to the risk of lynx predation. It is suggested that the decline of the lynx in the Donana area may have caused the increase in the population size of smaller, previously rarer carnivores. 6. The true relationship between lynx and foxes remains unclear, and badgers were apparently indifferent to lynx presence or absence.

We have monitored the number of arctic foxes and microtine rodents in northern Finland for 30 years. Arctic fox densities were estimated by inventories at den sites, and microtine abundance by snap trapping. Time series analyses showed that the arctic fox population fluctuated widely but always close together with the microtines in a five year cycle. However, there was no time lag in the numerical response of foxes on microtines. The strong dependence on microtines was confirmed by analyses of faecal droppings and food remains at dens. In summer time microtines consisted in average of 45% of the diet and reindeer 30%, but during winters reindeer was the most important food source with 45% compared to 15% for microtines. There was a surprising positive correlation between number of voles and reindeer carcasses, suggesting competition or alternatively an external correlation from e.g. weather. Mean litter size of the arctic fox was also highly dependent on microtine abundance but decreased during the study period despite that food resources had not changed. Further, when microtines had high densities during two consecutive years, arctic foxes only responded to the first year. A feeding experiment resulted in an increase in number of red foxes but had no or little effect on arctic foxes. So, it is difficult to single out one explanation to the decline and second year effect. Food was probably not involved and we do not know if diseases and parasites have been involved. However, both competition and predation, primarily from the red fox, may be responsible together with climatic or weather changes.

Foxes originally were absent from most Alaskan islands in the North Pacific. Red foxes (Vulpes vulpes) were indigenous to the Fox Islands in the eastern Aleutians and to some islands off the Alaska Peninsula and in the Gulf of Alaska. The first recorded introduction of foxes was in 1750 when Russians released arctic foxes (Alopex lagopus) from the Commander Islands on Attu, the westernmost island in the Aleutians. Russians released red and arctic foxes on other islands mainly in the early 1800's. By the 1930's, over 450 islands had been stocked mainly with arctic foxes for fur farming. During this period, the first government surveys and concerns about the effects of introduced foxes on insular avifauna arose, although Aleuts had indicated that seabirds were disappearing on some islands with introduced foxes as early as 1811. Besides foxes, Norway rats (Rattus norvegicus), ground squirrels (Spermophilus undulatus), and other mammals were introduced. Foxes eliminated populations of Aleutian Canada geese (Branta canadensis leucopareia) on all except three small islands. Populations of seabirds, particularly burrow-nesters, were also drastically reduced by foxes. Fox trappers regarded seabirds as feed.