Progress in the eradication of the feral cat and recovery of the native fauna on Socorro Is

Ortiz-Alcaraz, A., Aguirre-Muñoz, A., Arnaud, G., Galina-Tessaro, P., Rojas-Mayoral, E., Méndez-Sánchez, F., & Ortega-Rubio, A. (2017). Progress in the eradication of the feral cat (Felis catus) and recovery of the native fauna on Socorro Island, Revillagigedo Archipelago, Mexico. Therya, 8(1).

Socorro Island, in the Revillagigedo Archipelago, has the highest number of endemisms of any Mexican island. It provides habitat for 117 vascular plants, 26 % of which are endemic to the island. Also endemic to the island are one reptile and eight terrestrial bird species. However, the local ecosystem has been heavily degraded by exotic mammals over the past 140 years. The feral sheep (Ovis aries) has contributed to a 30% loss in habitat based on the island’s surface area. Another serious threat is the feral cat (Felis catus), which has severely impacted the island’s bird communities and the endemic Socorro tree lizard (Urosaurus auriculatus). Together, feral sheep and cats are responsible for the extinction in the wild of the Socorro dove (Zenaida graysoni) and the Socorro Elf Owl (Micrathene whitneyi graysoni), and pose a serious threat for other vulnerable species, such as the Townsend’s shearwater (Puffinus auricularis). The feral sheep was completely eradicated in 2012, which resulted in a rapid and remarkable recovery of the local vegetation cover. The eradication of the feral cat has been a complex issue to undertake due to the large size and topographical complexity of Socorro Island. In 2011 Grupo de Ecología y Conservacion de Islas, A. C. (GECI) started a feral cat control program, which scaled up into an eradication campaign. Here we report on the progress of the eradication campaign between 2011 and 2015, and provide a first assessment of the recovery of the native fauna. Beginning in 2011, camera traps were used to estimate cat abundance. Leg-hold and lethal traps were used to capture feral cats, some of them mounted with telemetry devices that alerted when traps were activated. Native vertebrates were monitored to confirm the positive effects derived from cat control efforts. By July 2015, 413 cats were dispatched using soft leg-hold and lethal traps, with a combined effort of 22,706 trap-nights. To date (mid-2016), cat abundance has decreased significantly, with cats being completely absent for several years in different areas of the island. The abundance of the endemic Socorro Island tree lizard and terrestrial birds has increased thanks to significant progress. Completing this important conservation action requires an increase in trapping efforts and the use of detection dogs, combined with night hunting. We estimate that the eradication of the feral cat will be completed by early 2017, after which the absence confirmation phase will begin.

Reduction in the capture success (%) of feral cats in the rainy and dry seasons from 2012 to 2015.

High-impact conservation: invasive mammal eradications from the islands of western Mexico

Aguirre-Muñoz, A., Croll, D. A., Donlan, C. J., Henry III, R. W., Hermosillo, M. A., Howald, G. R., ... & Samaniego-Herrera, A. (2008). High-impact conservation: invasive mammal eradications from the islands of western Mexico. AMBIO: A Journal of the Human Environment, 37(2), 101-107.

Islands harbor a disproportionate amount of the earth's biodiversity, but a significant portion has been lost due in large part to the impacts of invasive mammals. Fortunately, invasive mammals can be routinely removed from islands, providing a powerful tool to prevent extinctions and restore ecosystems. Given that invasive mammals are still present on more than 80% of the world's major islands groups and remain a premier threat to the earth's biodiversity, it is important to disseminate replicable, scaleable models to eradicate invasive mammals from islands. We report on a successful model from western México during the past decade. A collaborative effort between nongovernmental organizations, academic biologists, Mexican government agencies, and local individuals has resulted in major restoration efforts in three island archipelagos. Forty-two populations of invasive mammals have been eradicated from 26 islands. For a cost of USD 21 615 per colony and USD 49 370 per taxon, 201 seabird colonies and 88 endemic terrestrial taxa have been protected, respectively. These conservation successes are a result of an operational model with three main components: i) a tri-national collaboration that integrates research, prioritization, financing, public education, policy work, capacity building, conservation action, monitoring, and evaluation; ii) proactive and dedicated natural resource management agencies; and iii) effective partnerships with academic researchers in México and the United States. What is now needed is a detailed plan to eradicate invasive mammals from the remaining islands in the region that integrates the needed additional financing, capacity, technical advances, and policy issues. Island conservation in western México provides an effective approach that can be readily applied to other archipelagos where conservation efforts have been limited.

Home range of feral cats on Rota Is.

Leo, B. T., Anderson, J. J., Brand Phillips, R., & Ha, R. R. (2016). Home range estimates of feral cats (Felis catus) on Rota Island and determining asymptotic convergence 1. Pacific Science, 70(3), 323-331.

Feral cats (Felis catus) have been shown to be a main contributor to species decline throughout the world and are especially threatening to insular species that lack appropriate defense characteristics. To mitigate the impact of feral cats on threatened species, space-use data are commonly used to design control strategies. In this article we report on the performance of GPS datalogging collars and provide baseline information on daily space use and home ranges of feral cats that threaten an endangered species on Rota Island in the Commonwealth of the Northern Mariana Islands. Using 100% Minimum Convex Polygon (MCP), average adult male home range was 1.32 km²(n = 2) and average adult female home range was 0.22 km²(n = 3). Home ranges were deemed fully revealed if asymptotes were approached using incremental analysis. Currently, there is no objective method for assessing where an asymptote is approached. Here, we describe a methodology to do so with the application of a Michaelis-Menten model to incremental data. We conclude that GPS datalogging collars are a viable tool for feral cat location data collection on Rota Island and that the Michaelis-Menten model is useful for determining asymptotic convergence of incremental location data.

Removal of feral dogs by befriending them

Morley, C. G. (2006). Removal of feral dogs Canis familiaris by befriending them, Viwa Island, Fiji. Conservation Evidence, 3(3).

On a Fijian island a decision was made to remove feral dogs Canis familiaris as they were predating
upon endangered fauna. Rather than trapping or shooting, by offering food and gradually habituating
them to people, almost all were captured unharmed and moved to the main island of Fiji. 

Are Novel Invaders Necessarily Facing Naïve Native Species on Islands?

Gérard, A., Jourdan, H., Millon, A., & Vidal, E. (2016). Knocking on Heaven's Door: Are Novel Invaders Necessarily Facing Naïve Native Species on Islands?. PloS one, 11(3), e0151545.

The impact of alien predator species on insular native biota has often been attributed to island prey naïveté (i.e. lack of, or inefficient, anti-predator behavior). Only rarely, however, has the concept of island prey naïveté been tested, and then only a posteriori (i.e. hundreds or thousands of years after alien species introduction). The presence of native or anciently introduced predators or competitors may be crucial for the recognition and development of adaptive behavior toward unknown predators or competitors of the same archetype (i.e. a set of species that occupy a similar ecological niche and show similar morphological and behavioral traits when interacting with other species).
Here, we tested whether two squamates endemic to New Caledonia, a skink, Caledoniscincus austrocaledonicus, and a gecko, Bavayia septuiclavis, recognized and responded to the odor of two major invaders introduced into the Pacific islands, but not yet into New Caledonia. We chose one predator, the small Indian mongoose Herpestes javanicus and one competitor, the cane toad Rhinella marina, which belong respectively to the same archetype as the following two species already introduced into New Caledonia in the nineteenth century: the feral cat Felis catus and the golden bell frog Litoria aurea. Our experiment reveals that geckos are naïve with respect to the odors of both an unknown predator and an unknown competitor, as well as to the odors of a predator and a competitor they have lived with for centuries. In contrast, skinks seem to have lost some naïveté regarding the odor of a predator they have lived with for centuries and seem “predisposed” to avoid the odor of an unknown potential competitor. These results indicate that insular species living in contact with invasive alien species for centuries may be, although not systematically, predisposed toward developing adaptive behavior with respect to species belonging to the same archetype and introduced into their native range.

An examination of feral cats control techniques for the protection of critically endangered species

Leo, B. T. (2016). An examination of predator control techniques for the protection of critically endangered species (Doctoral dissertation).

Feral cats (Felis catus) have been shown to be a main contributor to species decline throughout the world and are especially threatening to insular species that lack adequate defense characteristics. Feral cat control programs have been implemented on islands throughout the world with varied success. Many islands present unique limitations and therefore require custom control strategies. Furthermore, the adaptive nature of feral cat populations makes it difficult to predict space use and the effect of control on population size. To mitigate the impact of feral cats on threatened species, space use data are commonly used to design control strategies. With the use of GPS data logging collars, chapter two describes daily space use and home ranges of feral cats that threaten an endangered species on Rota Island in the Commonwealth of the Northern Mariana Islands. Using 100% Minimum Convex Polygon (MCP), average adult male home range was 1.32 km² and average adult female home range was 0.22 km². Home ranges were deemed fully revealed if asymptotes were reached using incremental analysis. A Michaelis-Menten model was applied to predict home ranges of cats with datasets that did not show convergence. The ability of the model to estimate home ranges of cats with limited location datasets was evaluated by comparing predictions derived from truncations of the full time series of complete datasets. Findings suggest that cat management on Rota should be multifaceted in order to maximize the protection of endangered species and that the Michaelis-Menten model is a useful tool for home range analysis. Chapter three examines the Rota hunting strategy to determine its impacts on the population. A discrete form of the Schaefer model was applied to a 29-month time series of control data. A likelihood framework was used to determine maximum likelihood parameter estimates and calculate population projections to compare control strategies. Model results suggest that the hunting strategy on Rota was effective at initially reducing the cat population, however an unfeasible amount of effort would be required to maintain such a rate of decline. Findings show that it is feasible to maintain cat abundance at lower levels and suggest that a concentrated-effort strategy is preferable to a fixed-effort strategy. While more complex population model forms are available, the Schaefer model is well suited for assessing the impacts of limited predator control programs, such as the one conducted on Rota Island.

Impact of Samoan stray dogs on tourism

Beckman, M. (2015). Pilot study: influence of the Samoan dog population on visitors. SLU Sveriges lantbruksuniversitet

A range of public health and animal welfare problems has been shown to be associated with free-roaming dogs. With a high density of free-roaming dogs and with a major tourism industry, Samoan tourists are likely to be influenced by the presence of the dogs. The tourists are mainly from the Oceanic region; with New Zealand and Australia as the biggest contributors. The aim of this study was to examine the potential impacts of dogs on visitors to Samoa.
A questionnaire was handed out to 281 visitors all over Samoa, collecting opinions and information on visitors’ experiences and behaviour regarding the Samoan dogs. The data were collected and analysed.
Almost all of the respondents in this study had seen free-roaming dogs in Samoa (269/274) and half of these respondents were negatively affected by the dogs’ presence (137/211). A vast majority of respondents thought that dogs required better management in Samoa (222/274). A majority also thought there were too many strays in Samoa (188/277) and that they did not look well fed (180/274) or healthy (194/274). A vast majority of respondents had ever avoided contact with dogs (235/272). About a fourth of the respondents had witnessed inappropriate behaviour against dogs according to their own definition (66/262). More dogs were seen in Apia, the capital of Samoa, where dogs also were more commonly perceived as a problem. Respondents in this study showed a support for humane population management methods such as sterilisation and registration. A majority were supportive of humane euthanasia, but a vast majority were unsupportive of poisoning of strays.
Compared to similar studies in other tourist areas, respondents in this study showed a high concern of dogs. The greater problems with free-roaming dogs in Apia have earlier been shown in other urban areas.
Free-roaming dogs are a problem for the tourism industry in Samoa. The findings of this study, along with previous findings, present the need of improvement of the Samoan dog situation. The problem seems to be more urgent in Apia than in the rest of Samoa.

Cat vectored toxoplasmosis among the main causes of mortality in endangered Nene

Work, T. M., Dagenais, J., Rameyer, R., & Breeden, R. (2015). Mortality patterns in endangered Hawaiian geese (Nene, Branta sandvicensis). Journal of Wildlife Diseases, 51(3), 688-695.

Understanding causes of death can aid management and recovery of endangered bird populations. Toward those ends, we systematically examined 300 carcasses of endangered Hawaiian Geese (Nene; Branta sandvicensis) from Hawaii, Maui, Molokai, and Kauai between 1992 and 2013. The most common cause of death was emaciation, followed by trauma (vehicular strikes and predation), and infectious/inflammatory diseases of which toxoplasmosis (infection with Toxoplasma gondii) predominated. Toxicoses were less common and were dominated by lead poisoning or botulism. For captive birds, inflammatory conditions predominated, whereas emaciation, trauma, and inflammation were common in free-ranging birds. Mortality patterns were similar for males and females. Trauma predominated for adults, whereas emaciation was more common for goslings. Causes of death varied among islands, with trauma dominating on Molokai, emaciation and inflammation on Kauai, emaciation on Hawaii, and inflammation and trauma on Maui. Understanding habitat or genetic-related factors that predispose Nene (particularly goslings) to emaciation might reduce the impact of this finding. In addition, trauma and infection with T. gondii are human-related problems that may be attenuated if effectively managed (e.g., road signs, enforcement of speed limits, feral cat [Felis catus] control). Such management actions might serve to enhance recovery of this endangered species.

Long-term protection of seabird breeding colonies on Tasman Island through eradication of cats

Robinson, S., Gadd, L., Johnston, M., & Pauza, M. (2015). Long-term protection of important seabird breeding colonies on Tasman Island through eradication of cats. New Zealand Journal of Ecology, 39(2), 0-0.

A restoration programme was initiated in 2008 in response to high levels of seabird predation by feral cats (Felis catus) at Australia’s largest fairy prion (Pachyptila turtur) colony on Tasman Island, Tasmania. The primary knockdown involved aerial baiting with para-aminopropiophenone (PAPP) in meat baits. The efficacy of baiting was lower than expected resulting in trapping and hunting commencing earlier than planned. Cats were successfully eradicated over two weeks. Key to the success of the programme was the identification of a narrow window of low prey availability for cats. Post-eradication monitoring of the two most common seabird species, fairy prions and short-tailed shearwaters (Ardenna tenuirostris), showed positive signs towards population recovery. Prion activity increased three-fold and shearwater breeding success increased.

Cats and dogs among the threats to declining flying fox in Japan

Vincenot, C. E., Koyama, L., & Russo, D. (2015). Near Threatened? First Report of Unsuspected Human-Driven Decline Factors in the Ryukyu Flying Fox (Pteropus dasymallus) in Japan. Mammalian Biology-Zeitschrift für Säugetierkunde.

Japan hosts the largest population of the threatened Ryukyu flying fox (Pteropus dasymallus), which, in Taiwan, suffered a drastic decline leading to local extinctions and, in the Philippines, remains only on three small islands. Conservation of the species in Japan is therefore crucial. National and international assessments have been based only on local anthropogenic factors, such as habitat degradation, electrocution on power lines, and accidental entanglements.

Using face-to-face interviews of farmers of the Yaeyama islands (eastern part of the Ryukyu archipelago), we discovered that other significant human-driven causes of decline were overlooked in assessments. Most importantly, we report here for the first time on the illegal killing of this species by farmers because it feeds on crops. The bat has been killed by intense poisoning, beating, and netting. Other cases of illegal infringement of animal welfare principles by the general population were also encountered (i.e. confinement and mistreatment) but could not be quantified. Furthermore, we also determined the historical use of flying fox meat as a food source, which has also never been documented before. Finally, we identified emerging threats that were previously neglected in the assessments of the species’ conservation status, namely predation by feral or semi-feral cats and dogs, whose populations have been booming in recent years. These unexpected factors, especially the ongoing killing of P.d. yayeyamae, call into question the IUCN downlisting (EN- > NT) decided in 2008, when poisoning campaigns were actually culminating, and lead us to recommend the initiation of conservation actions (particularly population monitoring), education campaigns, as well as the provision of technical assistance to farmers in need of it.

Spatial ecology of feral cats on San Clemente Island

Bridges, A. S., Sanchez, J. N., & Biteman, D. S. (2015). Spatial ecology of invasive feral cats on San Clemente Island: implications for control and management. Journal of Mammalogy, 96(1), 81-89.

Feral cats, Felis catus, inhabiting San Clemente Island, California, are both predators and competitors of multiple sympatric endemic species. To improve our understanding and management of these invasive predators, we used GPS-equipped radiocollars to track 11 (6F:5M) cats for a total of 3,108 days, resulting in 15,419 GPS locations. Average 100% minimum convex polygon, 95% kernel density, and 50% kernel density estimates were 229, 132, and 33 ha, respectively. The point estimate for average male home-range size was larger than the average for females, but there was substantial variation among individuals of both sexes. Overlap indices indicated similar usage areas during nocturnal and diurnal time periods. Sample size limited our ability to definitively detect habitat preference, but data suggested areas within 50 m of roads were avoided, and that thicker land cover was preferred over open grasslands. Three test collars deployed within active cat home ranges indicated GPS locations were precise, with 96% of locations having < 10-m error estimates, and that horizontal dilution of precision indices were not useful in screening data. Our results describe feral cat spatial ecology on a semiarid island and can be used to inform population estimation, control, and mitigation programs.

Floreana Island rodent and cat eradication feasibility analysis

Island Conservation (2013) Floreana Island Ecological Restoration: Rodent and Cat Eradication
Feasibility Analysis version 6.0. Island Conservation, Santa Cruz, California. 85 pp.

The eradication of introduced vertebrates has become a widely accepted strategy for restoring island ecosystems. Based on an understanding of eradication methods and the Floreana Island project site, the feasibility of removing black rats, house mice, and feral cats is assessed within this document. Feasibility was assessed based on current techniques to safely remove rodents and feral cats from islands which have been used worldwide, including recent eradications within the Galápagos archipelago.
The goal of this project is to restore ecosystem function as well as enhance community well-being on Floreana Island. This would be achieved through the eradication of black rats, house mice and feral cats and by implementing effective biosecurity measures (e.g. preventing a rodent incursion and ensuring that domestic cats present on the island cannot act as a source population).
The most common technique used globally for removing rodents from islands is the application of bait containing a rodenticide. Cats are primarily targeted with poison, trapping, and hunting. Floreana is a large island (17,125 ha) compared to efforts undertaken elsewhere. If successful, it would be the second largest island to have had cats and rats removed and the largest to have had mice removed. Methods recommended for this multi-species eradication on Floreana Island are aerial- and ground-dispersed toxic baits (resulting in primary and secondary exposure of target populations), trapping, and hunting with and without dogs. To complement these actions, domestic cats must be sterilized and registered, euthanized, or removed from the island. Regulations must be implemented prior to the eradication to ensure that these actions can be applied to all domestic cats on the island, and that no cats can be imported to the island. Community buy-in and regulations will be required to allow access to all buildings and areas of the island, regardless of tenure. Additional recommendations are made regarding options for interisland biosecurity as well as legislation to regulate or prohibit importations of certain animals.
Factors such as a permanent community on island, tourism, and farmland/agriculture will complicate actions to eradicate rodents and cats. Although this is the case, all eradication principles can be met if the appropriate measures are taken during the planning, implementation, and confirmation phases. The technical removal of both rodents and cats is considered feasible with current eradication methods. Social, legal, and environmental acceptability has been assessed and is considered feasible within the region. Feasibility should be re-assessed periodically as results are received from processes to engage the community. A total cost of $10-12 million dollars is estimated for the planning and implementation of the recommended actions.
This document lays out a detailed description of the site and target species, recommended project approach, scope, and suggested stakeholder involvement needed to carry out a successful multispecies (mouse, rat, cat) eradication campaign on Floreana Island.

Cat eating endangered honeycreeper

The non-native feral cat in Hawaii is the most threatening predator to critically endangered palila. Palila did not evolve with these predators and are especially vulnerable to them. Evidence of their vulnerability was documented by researchers studying nest success of palila using continuous-loop video cameras to monitor the nests. Based on predation rates of the nests monitored, feral cats cause about 10% of all palila nests to fail every year.

Nest predation on endangered Hawaiian honeycreeper

Laut, M. E., Banko, P. C., & Gray, E. M. (2003). Nesting behavior of Palila, as assessed from video recordings. Pacific science, 57(4), 385-392.

We quantified nesting behavior of Palila (Loxioides bailleui), an endangered Hawaiian honeycreeper, by recording at nests during three breeding seasons using a black-and-white video camera connected to a videocassette recorder. A total of seven nests was observed. We measured the following factors for daylight hours: percentage of time the female was on the nest (attendance), length of attendance bouts by the female, length of nest recesses, and adult provisioning rates. Comparisons were made between three stages of the 40-day nesting cycle: incubation (day 1–day 16), early nestling stage (day 17–day 30 [i.e., nestlings ≤14 days old]), and late nestling stage (day 31–day 40 [i.e., nestlings > 14 days old]). Of seven nests observed, four fledged at least one nestling and three failed. One of these failed nests was filmed being depredated by a feral cat (Felis catus). Female nest attendance was near 82% during the incubation stage and decreased to 21% as nestlings aged. We did not detect a difference in attendance bout length between stages of the nesting cycle. Mean length of nest recesses increased from 4.5 min during the incubation stage to over 45 min during the late nestling stage. Mean number of nest recesses per hour ranged from 1.6 to 2.0. Food was delivered to nestlings by adults an average of 1.8 times per hour for the early nestling stage and 1.5 times per hour during the late nestling stage and did not change over time. Characterization of parental behavior by video had similarities to but also key differences from findings taken from blind observations. Results from this study will facilitate greater understanding of Palila reproductive strategies.

Videographic evidence of endangered species depredation by feral cat in Hawaii

Judge, S., Lippert, J. S., Misajon, K., Hu, D., & Hess, S. C. (2012). Videographic evidence of endangered species depredation by feral cat. Pacific Conservation Biology, 18(4), 293.

Feral cats (Felis catus) have long been implicated as nest predators of endangered 'Ua'u (Hawaiian Petrel; Pterodroma sandwichensis) on Hawai'i Island, but until recently, visual confirmation has been limited by available technology. 'Ua'u nest out of view, deep inside small cavities, on alpine lava flows. During the breeding seasons of 2007 and 2008, we monitored known burrows within Hawai'i Volcanoes National Park. Digital infrared video cameras assisted in determining the breeding behaviour and nesting success at the most isolated of burrows. With 7 cameras, we collected a total of 819 videos and 89 still photographs of adult and nestling 'Ua'u at 14 burrows. Videos also confirmed the presence of rats (Rattus spp.) at 2 burrows, 'Oma'o (Myadestes obscurus) at 8 burrows, and feral cats at 6 burrows. A sequence of videos showed a feral cat taking a downy 'Ua'u chick from its burrow, representing the first direct evidence of 'Ua'u depredation by feral cat in Hawai'i. This technique provides greater understanding of feral cat behaviour in 'Ua'u colonies, which may assist in the development of more targeted management strategies to reduce nest predation on endangered insular bird species.

Comparison of managed and unmanaged wedge-tailed shearwater colonies: Effects of predation

Smith, D. G., Polhemus, J. T., & VanderWerf, E. A. (2002). Comparison of managed and unmanaged wedge-tailed shearwater colonies on O'ahu: Effects of predation. Pacific Science, 56(4), 451-457.

On O‘ahu, Wedge-tailed Shearwaters (Puffinus pacificus) and other seabirds nest primarily on small offshore islets, but fossil evidence shows that many seabirds formerly bred on O‘ahu itself. Predation by introduced mammals is suspected to be the primary factor preventing shearwaters and other seabirds from reestablishing large nesting colonies on O‘ahu. We investigated the effects of predation on Wedge-tailed Shearwaters by comparing three small unmanaged colonies at Mālaekahana State Recreation Area on O‘ahu, where feral cats are fed by the public, with a large managed colony at nearby Moku‘auia Island State Seabird Sanctuary, where predators are absent. During three visits on 19 April, 16 June, and 23 October 2000, we located 69 occupied burrows in three colonies at Mālaekahana and 85 occupied burrows in four monitoring plots at Moku‘auia. Many more nests produced chicks at Moku‘auia (62%) than at Mālaekahana (20%). Among plots at Ma¯laekahana, reproductive success was lowest (zero) at the colony closest to the cat feeding site. In addition, 44 adult shearwater carcasses were found at Mālaekahana near the cat feeding site. Predation, most likely by cats attracted to supplemental food, had a devastating impact on shearwaters at Mālaekahana. At one colony there was complete reproductive failure and almost all adults were killed. Populations of long-lived species like seabirds are sensitive to adult mortality, and Ma¯laekahana may act as a sink, draining birds away from other areas.

Mongooses may be more dangerous predator than cats to burrowing seabirds

DUFFY, D. C. & CAPECE, P.I. 2014. Depredation of endangered burrowing seabirds in Hawai’i: management priorities. Marine Ornithology 42: 149–152.

Small Indian Mongooses Herpestes javanicus have until recently been absent from the island of Kaua’i, Hawai’i. In anticipation of required management, we examine evidence that mongooses may be a significantly more dangerous predator than cats Felis catus for burrowing seabirds, particularly the endangered Hawaiian Petrel Pterodroma sandwichensis and threatened Newell’s Shearwater Puffinus newelli. Mongooses are small enough to enter burrows, allowing them to take eggs, nestlings and adults. In contrast, cats appear too broad to enter any but the widest burrows, so they tend to attack adults and young when these come to the burrow mouth. Given that these seabird species no longer persist in any numbers at low elevations on islands where mongooses are present, and that Kaua’i is one of the lowest of the main Hawaiian islands, if resources are limited, local control or eradication of mongooses would be a higher priority for management than control of cats or rats Rattus spp., although control of just one predator might result in increases in the others. The most important management action is to keep mongooses off islands where they are not already established.

Adjustments to new predators in the Galapagos marine iguana

Berger, S., Wikelski, M., Romero, L. M., Kalko, E. K., & Rödl, T. (2007). Behavioral and physiological adjustments to new predators in an endemic island species, the Galapagos marine iguana. Hormones and behavior, 52(5), 653-663.

For the past 5 to 15 million years, marine iguanas (Amblyrhynchus cristatus), endemic to the Galápagos archipelago, experienced relaxed predation pressure and consequently show negligible anti-predator behavior. However, over the past few decades introduced feral cats and dogs started to prey on iguanas on some of the islands. We investigated experimentally whether behavioral and endocrine anti-predator responses changed in response to predator introduction. We hypothesized that flight initiation distances (FID) and corticosterone (CORT) concentrations should increase in affected populations to cope with the novel predators. Populations of marine iguanas reacted differentially to simulated predator approach depending on whether or not they were previously naturally exposed to introduced predators. FIDs were larger at sites with predation than at sites without predation. Furthermore, the occurrence of new predators was associated with increased stress-induced CORT levels in marine iguanas. In addition, age was a strong predictor of variation in FID and CORT levels. Juveniles, which are generally more threatened by predators compared to adults, showed larger FIDs and higher CORT baseline levels as well as higher stress-induced levels than adults. The results demonstrate that this naive island species shows behavioral and physiological plasticity associated with actual predation pressure, a trait that is presumably adaptive. However, the adjustments in FID are not sufficient to cope with the novel predators. We suggest that low behavioral plasticity in the face of introduced predators may drive many island species to extinction.

Attitudes of residents and tourists towards stray dogs in Samoa

Farnworth, M., Blaszak, K., Hiby, E. F., & Waran, N. K. (2012). Incidence of dog bites and public attitudes towards dog care and management in Samoa. Animal welfare. 21 : 477-486.

In many developing nations, dogs (Canis familiaris) present a significant issue in terms of human health, safety and animal welfare. We assessed attitudes towards dogs and their management in Samoa, a developing South Pacific island nation, using a questionnaire. It demonstrated that Samoa has one of the world’s highest recorded levels of household dog ownership (88%) but a comparatively low rate of vaccination (12%) and sterilisation (19%). Those interviewed believe dogs were important and should be considered part of the family; however most households reported that their dogs were kept for protection (79%). There was a clear skew in the sex distribution. The dog population showed a strong male bias (71%) suggesting females are removed from the population. Of those surveyed only 16% had received any education about dogs and their management and overall the respondents showed a clear disparity between attitudes and behaviour (eg the majority believe dogs should be vaccinated [81%] yet most dogs in this sample [72%] had never been to a veterinarian). Overall, there was a willingness to manage the free-roaming dog population which was considered by many to be a nuisance, however there were few enforceable mechanisms by which this could occur and most dogs were not confined. Harm or killing of dogs was relatively commonplace with 30% of households reporting they knew someone who had harmed or killed a dog and 26% of respondents indicating they believed harming or killing dogs was good for Samoan society, presumably by reducing problems associated with the free-roaming population. Dog bites were relatively frequent in Samoa and reports from two hospitals indicated a frequency of 37 new bites per annum requiring hospitalisation per 10,000 head of population. Furthermore, this paper outlines strategies and further research that could be considered to improve dog welfare and reduce the need to harm or kill dogs, namely improvements in veterinary provision and dog-focused education. It also considers the need for legislative controls and more research and funding to be made available for small developing nations to explore their animal welfare obligations.

Beckman, M., Hill, K. E., Farnworth, M. J., Bolwell, C. F., Bridges, J., & Acke, E. (2014). Tourists’ Perceptions of the Free-Roaming Dog Population in Samoa.Animals, 4(4), 599-611.

Simple Summary: For travelers, the way in which people in other nations interact with animals may be different to that in their home nation. This research explores how the treatment of dogs impacted upon the holiday experiences of tourists visiting a developing island nation. In general, and where tourists encountered dogs, their treatment was perceived as less positive than in their home country and had a negative impact upon the holiday experience. Although it is important to recognize that the local population will have a different worldview, tourists felt that the dog population required more effective management and were most supportive of techniques that were non-lethal and humane.
Abstract: A study was undertaken to establish how visiting tourists to Samoa perceived free-roaming dogs (Canis familiaris) and their management, additionally some factors that influence their perceptions were assessed. Questionnaires were administered to 281 tourists across Samoa over 5 weeks. Free-roaming dogs were seen by 98.2% (n = 269/274) of respondents, with 64.9% (n = 137/211) reporting that their presence had a negative effect on overall holiday experience. Respondents staying in the Apia (capital city) area were more likely to consider dogs a problem (p < 0.0001), and there was a significant association between whether the respondent owned a dog and if they thought dogs were a nuisance in Samoa (p < 0.003). Forty-four percent (20/89) of non-dog owners agreed that dogs were a nuisance compared to 22% (80/182) of dog owners. The majority felt that dogs required better control and management in Samoa (81%, n = 222) and that there were too many “stray” dogs (67.9%, n = 188). More respondents were negatively affected by the dogs’ presence (64.9%, 137/211), and felt that the dogs made their holiday worse, than respondents that felt the dogs’ presence improved their holiday experience (35.1%, 74/211). Most respondents stated that the dogs had a low impact (one to three; 68%, 187/275) on their stay in Samoa, whilst 24% (65/275) and 8% (23/275) stated they had a medium or high impact, respectively, on their stay. Respondents showed strong support for humane population management. Free-roaming dogs present a complex problem for Samoa and for its tourism industry in particular. The findings of this study further support the need for more discussion and action about the provision of veterinary services and population management for dogs in Samoa. It also provides information complementing an earlier study of the attitudes of local Samoans.

Origin of dingoes and Polynesian dogs

Oskarsson, M. C., Klütsch, C. F., Boonyaprakob, U., Wilton, A., Tanabe, Y., & Savolainen, P. (2011). Mitochondrial DNA data indicate an introduction through Mainland Southeast Asia for Australian dingoes and Polynesian domestic dogs. Proceedings of the Royal Society B: Biological Sciences, rspb20111395.

In the late stages of the global dispersal of dogs, dingoes appear in the Australian archaeological record 3500 years BP, and dogs were one of three domesticates brought with the colonization of Polynesia, but the introduction routes to this region remain unknown. This also relates to questions about human history, such as to what extent the Polynesian culture was introduced with the Austronesian expansion from Taiwan or adopted en route, and whether pre-Neolithic Australia was culturally influenced by the surrounding Neolithic world. We investigate these questions by mapping the distribution of the mtDNA founder haplotypes for dingoes (A29) and ancient Polynesian dogs (Arc1 and Arc2) in samples across Southern East Asia (n = 424) and Island Southeast Asia (n = 219). All three haplotypes were found in South China, Mainland Southeast Asia and Indonesia but absent in Taiwan and the Philippines, and the mtDNA diversity among dingoes indicates an introduction to Australia 4600–18 300 years BP. These results suggest that Australian dingoes and Polynesian dogs originate from dogs introduced to Indonesia via Mainland Southeast Asia before the Neolithic, and not from Taiwan together with the Austronesian expansion. This underscores the complex origins of Polynesian culture and the isolation from Neolithic influence of the pre-Neolithic Australian culture.

Frequency of the Polynesian haplotypes Arc1 and Arc2, and the dingo founder haplotype A29 in geographical regions. The number of individuals carrying each haplotype, total number of samples for the region and frequency (per cent) are shown. Arrows indicate suggested introduction routes. For Australia, A29 denotes both haplotypes A29 and A29′

Savolainen, P., Leitner, T., Wilton, A. N., Matisoo-Smith, E., & Lundeberg, J. (2004). A detailed picture of the origin of the Australian dingo, obtained from the study of mitochondrial DNA. Proceedings of the National Academy of Sciences of the United States of America, 101(33), 12387-12390.

To determine the origin and time of arrival to Australia of the dingo, 582 bp of the mtDNA control region were analyzed in 211 Australian dingoes sampled in all states of Australia, 676 dogs from all continents, and 38 Eurasian wolves, and 263 bp were analyzed in 19 pre-European archaeological dog samples from Polynesia. We found that all mtDNA sequences among dingoes were either identical to or differing by a single substitution from a single mtDNA type, A29. This mtDNA type, which was present in >50% of the dingoes, was found also among domestic dogs, but only in dogs from East Asia and Arctic America, whereas 18 of the 19 other types were unique to dingoes. The mean genetic distance to A29 among the dingo mtDNA sequences indicates an origin ≈5,000 years ago. From these results a detailed scenario of the origin and history of the dingo can be derived: dingoes have an origin from domesticated dogs coming from East Asia, possibly in connection with the Austronesian expansion into Island Southeast Asia. They were introduced from a small population of dogs, possibly at a single occasion, and have since lived isolated from other dog populations.