Inefficient TNR

Kilgour, R. J., Magle, S. B., Slater, M., Christian, A., Weiss, E., & DiTullio, M. (2016). Estimating free-roaming cat populations and the effects of one year Trap-Neuter-Return management effort in a highly urban area. Urban Ecosystems, 1-10.

Free-roaming cat populations are increasing in urban areas around the world. Management strategies remain controversial, as attempts to rapidly minimize the impact of cats may conflict with finding an ethical means of population reduction in this domesticated species. Trap-Neuter-Return (TNR) is a non-lethal strategy which can theoretically lead to population decline with an ethical approach. The present study aimed to estimate free-roaming cat populations and also to measure the efficacy of a one-year TNR campaign in a highly urban area. Using a sight/resight methodology, we examined free-roaming cat populations in four sites across two neighbourhoods (Harlem and Bedford-Stuyvesant) in New York City. Sampling was repeated after 1 year, during which an intensive TNR effort occurred in each of those areas. Results from this study found population estimates range from 2.6-4.1 cats/km. Additionally, we found between 78-98% turnover in each study area. After one year of TNR, the proportion of sterilised individuals in our treatment sites increased to 50%. Model results suggest there is no evidence that sterilised individuals are more likely to be encountered, indicating that sterilisation may not affect movement patterns of cats. Free-roaming cats occur at high densities at all study sites, though populations varied, even within the same neighbourhood. We found evidence of considerable migration within study sites, which further complicates the application of a sterilisation management strategy. Management strategies directed toward free-roaming cats, such as TNR, may require a broad-scale approach, involving different facets of the community and should occur over multiple years.

Domestic dogs as nest predators of Wilson’s plover in northeastern Brazil

Diniz, C. G., de Morais Magalhães, N. G., Guerreiro, D., Diniz, P. D. C. P., Paulo, D. C., Renato, F., ... & Diniz, C. W. P. (2016). Cães domésticos predadores de ninho de batuíra bicuda (Charadrius wilsonia) no nordeste brasileiro. Revista da Biologia, 16(1), 24-27. 

Although Wilson´s plovers (Charadrius wilsonia) are migratory, a resident population breeds in coastal northeastern Brazil and there population trend is described as decreasing by the IUCN Red List. Domestic dogs are a major predator of Wilson’s plover nests on an island in northeastern Brazil where dogs are kept to guard fishing equipment. Local fishermen, however, are motivated to protect the nests of shorebirds and when shown video recordings documenting nest predation acted quickly to remove dogs. We found that providing local residents with evidence about the causes of nest
predation could play an effective role in protecting bird populations.

Live-capture of feral cats using different methods

McGregor, H. W., Hampton, J. O., Lisle, D., & Legge, S. (2016). Live-capture of feral cats using tracking dogs and darting, with comparisons to leg-hold trapping. Wildlife Research, 43(4), 313-322.

Context: Predation by feral cats is a key threatening process to many species of native Australian wildlife. Unfortunately, cats are difficult to capture using standard trapping techniques, limiting the potential to conduct research on their ecology and impacts.

Aims: We present an alternative capture method: remote chemical immobilisation after tracking with trained dogs. We also compare capture rates to a concurrent soft-jaw leg-hold trapping program.

Methods: We used dogs to capture cats detected by spotlighting at night, and also recaptured cats fitted with telemetry collars during the day. Cats were either bailed on the ground or treed and then hand-netted, or chemically immobilised using darts shot from a CO2-powered dart rifle, loaded with tiletamine–zolazepam at ~6 mg kg–1. Factors affecting the success rate of capturing cats using dogs were assessed. Efficiency in terms of cats captured per person-hours of fieldwork were compared using trained dogs versus leg-hold trapping.

Key results: We attempted 160 cat captures using the tracking dogs with 114 of those being successful. There were no mortalities or debilitating physical injuries associated with chemical immobilisation; however, sedated cats had prolonged recoveries (>4 h). Capture success with the tracking dogs increased as the dogs gained experience. Capture success rates per person-hour of fieldwork were four times greater using spotlighting with tracking dogs than using leg-hold traps. The success rate of recaptures using dogs was 97%.

Conclusions: The use of trained tracking dogs proved an effective method for capturing feral cats. The method had a much higher success rate than live-trapping with leg-hold traps, took less effort (in terms of person-hours) and caused less physical injuries than did leg-hold traps. However, substantial setup costs and time are required, which are discussed.

Implications: Using these methods could improve efficiency and outcomes when catching feral cats, and enable more data per individual cat to be collected than otherwise.

Implications for human-wolf conflict due to free-roaming domestic dogs predation on deer in southern Spain:

Duarte, J., García, F. J., & Fa, J. E. (2016). Depredatory impact of free-roaming domestic dogs on Mediterranean deer in southern Spain: implications for human-wolf conflict. Folia Zoologica, 65(2).

Feral domestic dogs are efficient wild ungulate hunters in many parts of the world. This has not been confirmed in Mediterranean ecosystems. However, if feral dogs can predate upon wild Mediterranean ungulates, they can also do so upon livestock. Therefore, to more realistically understand human-wolf conflict in areas where wolves and feral dogs overlap, the possible role of the latter taking domestic prey should be considered. During a 6-month study period, we carried out daily observations of a pack of mediumsized dogs, where they were the only large-bodied carnivore capable of killing ungulates in a fenced estate in southern Spain. The estate contained sizeable populations of red deer, fallow deer and mouflons, but no livestock. We described feral dog predation patterns and depredatory impact. We found that dogs predated upon a total of 57 ungulates; fallow deer (47 %), red deer (37 %), and mouflon (16 %). Red deer adults were the least frequent prey, but dogs killed significantly more females and fawns of red and fallow deer. Mouflons were attacked indistinctly. Our results suggest that dogs in our study exhibited a kill pattern similar to Iberian wolves. Therefore, in areas where wolves and feral dogs coexist, a significant proportion of livestock predation could be falsely attributed to the wild canid. In addition, the presence of feral dogs may be a cause of risk in big game hunting estates.

CDV in wild endangered Amur tigers

Seimon, T. A., Miquelle, D. G., Chang, T. Y., Newton, A. L., Korotkova, I., Ivanchuk, G., ... & McAloose, D. (2013). Canine distemper virus: an emerging disease in wild endangered Amur tigers (Panthera tigris altaica). MBio, 4(4), e00410-13.


Fewer than 500 Amur tigers (Panthera tigris altaica) remain in the wild. Due to low numbers and their solitary and reclusive nature, tiger sightings across their range in the Russian Far East and China are rare; sightings of sick tigers are rarer still. Serious neurologic disease observed in several wild tigers since 2001 suggested disease emergence in this endangered species. To investigate this possibility, histology, immunohistochemistry (IHC), in situ hybridization (ISH), and reverse transcription-PCR (RT-PCR) were performed on tissues from 5 affected tigers that died or were destroyed in 2001, 2004, or 2010. Our results reveal canine distemper virus (CDV) infection as the cause of neurologic disease in two tigers and definitively establish infection in a third. Nonsuppurative encephalitis with demyelination, eosinophilic nuclear viral inclusions, and positive immunolabeling for CDV by IHC and ISH were present in the two tigers with available brain tissue. CDV phosphoprotein (P) and hemagglutinin (H) gene products were obtained from brains of these two tigers by RT-PCR, and a short fragment of CDV P gene sequence was detected in lymph node tissue of a third tiger. Phylogenetically, Amur tiger CDV groups with an Arctic-like strain in Baikal seals (Phoca siberica). Our results, which include mapping the location of positive tigers and recognition of a cluster of cases in 2010, coupled with a lack of reported CDV antibodies in Amur tigers prior to 2000 suggest wide geographic distribution of CDV across the tiger range and recent emergence of CDV as a significant infectious disease threat to endangered Amur tigers in the Russian Far East.

IMPORTANCE Recognition of disease emergence in wildlife is a rare occurrence. Here, for the first time, we identify and characterize a canine distemper virus (CDV), the second most common cause of infectious disease death in domestic dogs and a viral disease of global importance in common and endangered carnivores, as the etiology of neurologic disease and fatal encephalitis in wild, endangered Amur tigers. We establish that in 2010 CDV directly or indirectly killed ~1% of Amur tigers. Location of positive cases over an expansive geographic area suggests that CDV is widely distributed across the tiger range. Interspecies interactions are increasing as human populations grow and expand into wildlife habitats. Identifying animal reservoirs for CDV and identifying the CDV strains that are transmissible to and among wildlife species, including Amur tigers and sympatric critically endangered Amur leopards (Panthera pardus orientalis), is essential for guiding conservation and mitigation efforts.

TNR and TVHR as methods to control nuisance from feral cats

Ireland, T., & Neilan, R. M. (2016). A spatial agent-based model of feral cats and analysis of population and nuisance controls. Ecological Modelling, 337, 123-136.

Free-roaming feral cats are common in areas of concentrated human habitation, and can pose considerable threats of nuisance and damage to native ecosystems. Trap-neuter-return (TNR) and trap-vasectomy-hysterectomy-return (TVHR) are two humane methods for the reproductive control of feral cat populations. Both TNR and TVHR render a cat infertile, but cats that have undergone TVHR continue to produce hormones that drive mating behaviors. We built a stochastic agent-based computational model for simulating the survival, reproduction, and movement of individual feral cats and the use of TNR and TVHR to modify cats’ reproductive abilities and behaviors. Daily movement of cats between colonies is implemented based on the distance between colonies and landscape properties (e.g. rural, urban). Spatially targeted TNR and TVHR policies are evaluated using two management goals: (1) reduce total population size and (2) reduce nuisance attributed to feral cats. Nuisance includes spraying and noise, both of which are associated with un-neutered males, as well as population abundance. Results indicate that both TNR and TVHR have the potential to greatly reduce population size. Effectiveness of each control depends on the capture rate, number of colonies targeted, size of each colony, and movement of individual cats between colonies. Results show that on average TVHR performs moderately better than TNR at reducing population size, but TNR substantially outperforms TVHR in reducing multiple nuisance measures.

Cross-species transmission of CDV

Beineke, A., Baumgärtner, W. & Wohlsein, P. 2015. Cross-species transmission of canine distemper virus-an update. One Health 1, 49–59.

Canine distemper virus (CDV) is a pantropic morbillivirus with a worldwide distribution, which causes fatal disease in dogs. Affected animals develop dyspnea, diarrhea, neurological signs and profound immunosuppression. Systemic CDV infection, resembling distemper in domestic dogs, can be found also in wild canids (e.g. wolves, foxes), procyonids (e.g. raccoons, kinkajous), ailurids (e.g. red pandas), ursids (e.g. black bears, giant pandas), mustelids (e.g. ferrets, minks), viverrids (e.g. civets, genets), hyaenids (e.g. spotted hyenas), and large felids (e.g. lions, tigers). Furthermore, besides infection with the closely related phocine distemper virus, seals can become infected by CDV. In some CDV outbreaks including the mass mortalities among Baikal and Caspian seals and large felids in the Serengeti Park, terrestrial carnivores including dogs and wolves have been suspected as vectors for the infectious agent. In addition, lethal infections have been described in non-carnivore species such as peccaries and non-human primates demonstrating the remarkable ability of the pathogen to cross species barriers. Mutations affecting the CDV H protein required for virus attachment to host-cell receptors are associated with virulence and disease emergence in novel host species. The broad and expanding host range of CDV and its maintenance within wildlife reservoir hosts considerably hampers disease eradication.

Genetic traces of historical human‐mediated dispersal of feral cats

Koch, K., Algar, D., & Schwenk, K. (2016). Feral Cat Globetrotters: genetic traces of historical human‐mediated dispersal. Ecology and Evolution.

Endemic species on islands are highly susceptible to local extinction, in particular if they are exposed to invasive species. Invasive predators, such as feral cats, have been introduced to islands around the world, causing major losses in local biodiversity. In order to control and manage invasive species successfully, information about source populations and level of gene flow is essential. Here, we investigate the origin of feral cats of Hawaiian and Australian islands to verify their European ancestry and a potential pattern of isolation by distance. We analyzed the genetic structure and diversity of feral cats from eleven islands as well as samples from Malaysia and Europe using mitochondrial DNA (ND5 and ND6 regions) and microsatellite DNA data. Our results suggest an overall European origin of Hawaiian cats with no pattern of isolation by distance between Australian, Malaysian, and Hawaiian populations. Instead, we found low levels of genetic differentiation between samples from Tasman Island, Lana'i, Kaho'olawe, Cocos (Keeling) Island, and Asia. As these populations are separated by up to 10,000 kilometers, we assume an extensive passive dispersal event along global maritime trade routes in the beginning of the 19th century, connecting Australian, Asian, and Hawaiian islands. Thus, islands populations, which are characterized by low levels of current gene flow, represent valuable sources of information on historical, human-mediated global dispersal patterns of feral cats.

Map of the world representing the main route (Golden Round) used by maritime fur trade (black lines). Boxes show sampling locations in Australia, Hawaii, and South-East Asia with bars indicating graphical output from STRUCTURE analysis for K = 5. Each individual cat is represented by a single vertical line in population's subset plots, which were assigned to their place of origin.

Zoonoses in pets of homeless

Edwards, M. P. (2016). GI Zoonoses in Companion Pets of the Homeless: The Effects of Environment, Behavior and Veterinarians on the Prevalence of GI Parasites. Bachelor of Science in

University Honors and Biology

Veterinarians are the front-line in the world of pet-health and zoonoses, which in turn means they also are at the front-line of human health and have an important role of educating clients on behaviors that would both reduce the risk of human and pet contracting a disease. In this study we collected 85 canine stool samples at at a charitable veterinary clinic for homeless and low-income individuals in Portland, Oregon. Prevalence of parasites was found to be 27.1%, including 2.4% Ancylostoma sp., 4.7% Cryptosporidium sp., 7.1% Isopora sp., 9.4% Taenia sp., 2.4% Giardia sp., and 2.4% Toxocara sp. In addition to sampling, a questionnaire surveyed owner and animal demographics, risk behaviors, owner risk perception and owner education surrounding zoonoses and deworming protocols. Of the risk factors surveyed, socialization with dogs, living environment (unstable and transitional), and pet gender (male) all were associated with increased parasite prevalence. In contrast, dog park use had a negative correlation with prevalence, suggesting exposure elsewhere despite dog park environmental contamination. Notably, individuals who dewormed their pet on a symptomatic basis had similar prevalence to those who never deworm; deworming as little as annually reduced the risk of pet infection by 75%. Furthermore, over 20% of asymptomatic pets were parasitized, over double the expected (5-10%). Lastly, the majority of the population surveyed (67.2%) had little knowledge of zoonoses or the potential for animal to human transmission. Pet owners indicated they were well informed by veterinarians about deworming frequencies, but not about zoonoses. Veterinarians have a duty to educate clients on the importance of regular screening and deworming regardless of symptoms, particularly in light of the zoonotic potential of many parasites.

Characterizing clinics involved in controlling stray cats

D'Ávila, A. M. E. D. (2016). Caracterização dos Centros de Atendimento Médico-Veterinários no Concelho de Lisboa que participam no controlo da população de gatos errantes e assilvestrados. Universidade Lusófona de Humanidades e Tecnologias. Faculdade de Medicina Veterinária

The presence of stray and feral cats in urban areas often leads to situations of overpopulation whereby the control of reproduction has proven to be a priority element in solving this problem. The primary goal of this study was to characterize the clinics in the Lisbon area in controlling the population of stray cats and to determine their impact on reducing the number of animals. To accomplish this, it has been developed a questionnaire submitted to clinical directors. Of the 44 participants, it was found that 52% participates in population control programs. The secondary goals were to evaluate protocols applied in relation to neutering and it was verified that most procedures performed in these cases follow the recommendations made by the specialized agencies, including the type of surgery (95,6% neuter and 100% spay), preanesthetic protocols, performing surgeries in pregnant cats (91,3% perform against 8,7% that does not perform), the use of nonsteroidal anti-inflammatory drugs (91% use them against 9% that does not use them), the use of fluidtherapy (65% use it against 35% that does not use it), the location of the postoperative period, the FIV-FeLV testing (78,26% does not test against 21,74% that does test) and the practice of left ear-cutting (86,96% cut against 13,04% that does not cut). On the contrary, performing sterilization on pre-pubertal cats is not followed (only 21,7% on males and 34,8% on females neuter before 6 months of age) and the use of antibiotics by the clinical staff is considered excessive (91% use them against 9% that does not use them) to the recommended parameters. In addition, using likelihood ratios established in the literature, it was also determined that the 2538 surgeries performed annually by this sample, prevent the birth of 6396 kittens and the wandering of 1599 cats, demonstrating the important role of clinics in fighting overpopulation of stray cats in Lisbon.

Urban cat ecology in Barcelona

Guerra, I. D. C. L. (2016). Ecologia urbana do gato doméstico Felis silvestris catus na cidade de Barcelona (Doctoral dissertation, Universidade Lusófona de Humanidades e Tecnologias).


Free life cats (Felis silvestris catus) are now common in urban areas and organize themselves in colonies associated with human presence and food availability. In Barcelona, there is a project of trap-neuter-return (TNR) of these cats.
From the 2013 data, a retrospective study, of the transverse observational type, was done of the free life cats and the ones with an owner. There is a direct relationship between the number of cats and the number of colonies (p = 0,004). The number of colonies is associated with the number of people (p = 0,004). Green areas, which can offer environmental resources, are directly related to the number of cats (p = 0,022) and to large colonies (p = 0,006). On the other hand, the area of the road network, which leads to habitat fragmentation, is directly associated with the number of colonies (p = 0,043) and also with small colonies (p = 0,023). Medium-sized colonies have a direct association with green areas (p = 0,035) and number of people (p = 0,026). The district area has a direct association with average-sized (p = 0,008) and large colonies (p = 0,043) as well as the number of cats (p = 0,005).

Potential transmision of dog pathogens to wild carnivores in India

Chaudhary, V. (2016). Threats of Disease Spillover from Domestic Dogs to Wild Carnivores in the Kanha Tiger Reserve, India. MSc disertation  Graduate School of Clemson University.

Many mammalian carnivore species persist in small, isolated populations as a result of habitat destruction, fragmentation, poaching, and human conflict. Their small numbers, limited genetic variability, and increased exposure to domestic animals such as dogs place them at risk of further losses due to infectious diseases. In India, dogs ranging from domestic to feral are associated with villages in and around protected areas, and may serve as reservoirs and vectors of pathogens to the carnivores within. India’s Kanha Tiger Reserve (KTR) is home to a number of threatened and endangered mammalian carnivores including tigers (Panthera tigris), leopards (Panthera pardus), wolves (Canis lupus), and dhole (Cuon alpinus). It also contains hundreds of small villages with associated dog populations, and my goal was to determine whether these dogs pose a disease threat to KTR’s wild carnivores. In the summer of 2014 and again in the winter of 2015 I estimated the density of dogs in villages of varying sizes and distances from KTR’s core zone, and the exposure of these dogs to four pathogens that could threaten wild carnivores: rabies, canine parvovirus (CPV), canine distemper (CDV), and canine adenovirus (CAV). Dog population densities ranged from 3.7 to 23.7/km²(14 to 45 dogs/village), and showed no systematic variation with village area or human population size. These dog populations grew in all villages between the summer of 2014 and winter of 2015, primarily through reproduction. No dog tested positive for rabies but I found high levels of seroprevalence to the other three pathogens: CPV (83.6% in summer 2014,
68.4% in winter 2015), CDV (50.7% in summer 2014, 30.4% in winter 2015) and CAV (41.8% in summer 2014, 30.9% in winter 2015). The declines in seroprevalence between summer and winter were primarily due to births in the population, of animals not exposed to the viruses. I opportunistically documented interactions between the dogs and wild carnivores that might allow disease transmission. I measured these interactions as the presence of wild carnivores in surveyed villages. In this study I document the existence of a large population of unvaccinated dogs in and around KTR, with high levels of seroprevalence to pathogens with broad host ranges. These dogs also have frequent contact with wild carnivores. I conclude that these dogs pose a high risk of disease spillover to wild carnivores in the region.
I also tested for CPV and CDV in wild carnivore samples obtained from the KTR Forest Department from 2010 to 2015. While one tiger blood sample was seropositive for CPV antibodies, the reverse transcriptase polymerase chain reaction found no evidence of CPV in tissue samples from five tigers, one leopard and one palm civet (Paradoxurus hermaphroditus), and no CPV or CDV in the three blood samples of tigers. Despite these results, I argue for continued surveillance in KTR, given the ubiquity of village dogs in the area with high seroprevalence of CDV and CPV and the contact between dogs and endangered carnivores in KTR. 

Ecological impact of free-ranging dogs in Poland

Wierzbowska, I. A., Hędrzak, M., Popczyk, B., Okarma, H., & Crooks, K. R. (2016). Predation of wildlife by free-ranging domestic dogs in Polish hunting grounds and potential competition with the grey wolf. Biological Conservation, 201, 1-9.

Although the domestic dog (Canis familiaris) is a ubiquitous exotic predator that can detrimentally affect natural environments, studies on their ecological impact are relatively scarce, particularly at a national scale. We exploited data derived from Polish Hunting Association reports to provide a national evaluation of rural free-ranging dogs in Poland. Our results demonstrate that free-ranging dogs are widespread and abundant, frequently killing wildlife and livestock in Poland and likely exerting intraguild competition with native carnivores such as grey wolves (Canis lupus). On average, hunting club records estimate that over 138,000 rural free-ranging dogs occurred annually in hunting grounds. In addition, nearly 3000 free-ranging greyhounds and their mixed breeds occurred annually on hunting grounds, although greyhound hunting has been banned in Poland and they are legally required to be restrained within fencing. On average, over 33,000 wild animals and 280 livestock were killed by free-ranging dogs on Polish hunting grounds annually. The number of both wild animals and livestock killed by dogs were strongly and positively correlated with the numbers of rural free-ranging dogs recorded on hunting grounds, reflective of their predation pressure. Also, the number of wild animals killed by dogs was positively correlated with estimates of population sizes and harvest levels of wildlife, reflective of prey availability. Dog predation, in conjunction with harvest by humans, may cause unsustainable off-take rates of some game species. Grey wolves, documented within 39 of the 49 Hunting Districts, ate similar prey as dogs, including ungulates and livestock, and killed dogs on hunting grounds, suggesting both resource and interference competition between these sympatric canids. This comprehensive analysis provides important information about the ecological impact of free-ranging dogs and recommendations for alternative legislative and management measures to control their impacts.