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Abstract Although the domestic cat Felis catus is implicated in multiple faunal extinctions and threatens many extant species, there is widespread, well‐funded advocacy for desexing unowned cats near human habitation and returning them to site to be fed by volunteers, arguing that this prevents euthanasia, is unlikely to be hazardous to wildlife or a public health risk, and controls non‐native rodents. To the contrary, we present unequivocal evidence that this approach harms cat welfare, does threaten wildlife and public health, and exacerbates rather than controls rodent problems. We argue instead that unowned cats near human habitation can be controlled effectively by intensive adoption and responsible euthanasia when necessary, supported by licensing and containment of adopted/owned cats.

Cats are popular companion animals globally. While the general academic definition of responsible cat ownership is agreed upon, committing to responsible cat ownership is multifaceted, often reflecting regional priorities and values. Utilising a virtual private network (VPN), an English-language online search for ‘responsible cat ownership’ was applied from major cities in 10 different nations, accounting for five different geographic regions and nine different geographic sub-regions. Data were extracted from the first 20 webpages of each search and included author affiliation, country of webpage origin, and all recommendations towards responsible cat ownership. Searches identified 58 different webpages, 142 duplicate results, and 16 different recommendations. Both before (60.5%) and after (58.6%) duplicate exclusion, irrespective of region, most webpages originated from Australia, so recommendations may lack local nuance in other countries. Similarly, local government webpages were the most common author affiliation both before (35.5%) and after (37.9%) duplicate exclusion—moreover, most Australian webpages were authored by local government (55.9%). More than half of all webpages recommended registration and microchipping (65.5%), desexing (65.5%), and containment (60.3%), probably due to the predominance of local government and Australian webpages online—reflecting Australia’s strong legislative stance. Both Australia and New Zealand showed majority recommendations for containment but not for environmental and behavioural enrichment in households. This may be partially explained by the significantly higher agreement in Australia and New Zealand that cats threaten valued wildlife in cities, towns, and rural areas. Unlike the Oceanian nations, other countries clearly recommended improved understanding and provision for cat needs, but with little evidence of support for containment. Thus, divergent welfare considerations inform major webpages associated with attitudes towards cat ownership internationally. Encouraging containment, a responsible cat ownership practice with benefits for cats and wildlife, may be more likely to succeed outside Oceania if cat welfare is emphasised instead of wildlife protection. Within Oceania, more attention could be given to enhancing the well-being of contained cats.

Globally, unowned urban cats are a major concern because they may suffer from poor welfare and cause problems, including public health risks, nuisances, and urban wildlife predation. While management options are often presented as a choice between culling or trap–neuter–return (TNR), for 25 years, the Lonely Miaow (Inc.) charity in Auckland, New Zealand (hereafter LM), has used a third strategy—intensive adoption or trap–assess–resolve (TAR). As of 2019, of 14,611 unowned cats trapped, 64.2% were adopted, 22.2% were euthanized if unsocialised or in grave ill-health, 5.7% were neutered and returned to the site, and 7.9% had other outcomes, such as being transferred to other shelters. Adoption rates increased over this time, exceeding 80.0% in 2018 and 2019. The cost of processing each cat from capture to adoption rose from NZD 58 in 1999 to NZD 234 by 2017. Approximately 80% of colonies (sites where cats were trapped) were around residential areas. Approximately 22% of cats required veterinary treatment after capture; common ailments included respiratory infections, ringworm, dental problems, and trauma. Consistently, 52% of cats were young kittens (c. 80% of cats were c. 2% were estimated to be >5 years old. TAR avoids euthanasia where possible. Its effectiveness would be enhanced by fewer abandonments of owned cats and kittens, fitting within integrated strategies for the control of unowned cats involving community education. Cat adoptions improve the welfare of cats and, with appropriate husbandry, should alleviate concerns about nuisances, public health, and attacks on wildlife or the cats themselves, essentially benefitting the community and the cats. This case study is relevant to other cities around the world that are seeking to manage unowned cats.

Trap–Neuter–Return and its variants (hereafter TNR) aims to control unowned cat populations. Papers on this topic form a useful case study of how how an area of literature grows, papers become influential, and citation networks form, influencing future study as well as public perceptions of the science. We analysed 145 TNR studies published 2002–2019. Common topics, identified by frequently used language, were population control, interactions with wildlife, disease transmission (including implications for pets, wildlife and humans), free-roaming cats, and feral and domestic cat management. One or more papers on each of these topics was judged influential because of high citations overall, high average citations/year, or frequent mentions in social media. Open Access papers were more influential in social media, raising greater public awareness than studies published in journals that were less accessible. While divergent views exist on a range of topics, the network analysis of the TNR literature indicated potential for forming self-reinforcing groups of authors. While it is encouraging that diverse views are expressed, there is a risk of reduced dialogue interactions between groups, potentially constraining dialogue to refine arguments, share information, or plan research. Journal editors could encourage communication by choosing reviewers from different camps to assess manuscripts and by asking authors to acknowledge alternative views.

As carnivorans rely heavily on their head and jaws for prey capture and handling, skull morphology and bite force can therefore reflect their ability to take larger or more difficult-to-handle prey. For 568 feral and stray cats (Felis catus), we recorded their demographics (sex and age), source location (feral or stray) and morphological measures (body mass, body condition); we estimated potential bite force from skull measurements for n = 268 of these cats, and quantified diet composition from stomach contents for n = 358. We compared skull measurements to estimate their bite force and determine how it varied with sex, age, body mass, body condition. Body mass had the strongest influence of bite force. In our sample, males were 36.2% heavier and had 20.0% greater estimated bite force (206.2 ± 44.7 Newtons, n = 168) than females (171.9 ± 29.3 Newtons, n = 120). However, cat age was the strongest predictor of the size of prey that they had taken, with older cats taking larger prey. The predictive power of this relationship was poor though (r2 < 0.038, p < 0.003), because even small cats ate large prey and some of the largest cats ate small prey, such as invertebrates. Cats are opportunistic, generalist carnivores taking a broad range of prey. Their ability to handle larger prey increases as the cats grow, increasing their jaw strength, and improving their hunting skills, but even the smallest cats in our sample had tackled and consumed large and potentially ‘dangerous’ prey that would likely have put up a defence.

To continue dialogue over proposed Australian trials of Trap-Neuter-Return (TNR), we applied a framework requiring identification of areas of agreement, areas of disagreement, and identification of empirical data collection required to resolve disagreements. There is agreement that Australia has a problem with stray cats, causing problems of impacts on wildlife, nuisance, disease transmission (including public health issues and exchange of diseases between stray cat and pet cat populations), poor welfare outcomes for stray cats, and an emotional burden on staff euthanising healthy stray cats. There is disagreement on whether (i) current measures are failing, leading to unacceptably high euthanasia levels, (ii) some contributors to the debate misunderstand TNR, (iii) TNR trials will reduce urban cat populations and associated problems, (iv) TNR is an ethical solution to cat overpopulation, and (v) some contributors to the debate promulgated misinformation. Although not everyone agrees that TNR trials should proceed, as a hypothetical exploration, we propose an experimental approach explicitly comparing TNR to alternatives. Trials could only be considered if other detailed and well-funded attempts at stray cat control focusing across an entire Local Government Area (LGA) prove ineffective.

Urban environments are increasingly important for biodiversity conservation, but pet cats threaten wildlife therein, displaying nuisance behaviour such as hunting, fighting, fouling and urine spraying. In an attempt to empower landholders wishing to reduce cat incursions humanely, we tested the effectiveness of two ultrasonic cat deterrents (CatStop© and On-Guard Mega-Sonic Cat Repeller©).After confirming in arena trials that cats detect and respond negatively to an ultrasonic device, we tested both deterrents in 18 suburban gardens in Perth, Western Australia. Camera monitoring at foci of cat activity (e.g. fish ponds, property entry/exit points) occurred for two weeks before (Period 1: device off), during (Period 2: device on) and after (Period 3: device off) the activation of deterrents. Data included individual cat demographics and behaviours, number of cat detections per site per day per sampling period, the duration of cat activity, and detection of non-target species.Seventy-eight unique cats were detected at 17 of 18 garden sites (2–9 cats/garden). Over half the cats could be sexed (56.4%, with 65.1% males). Nearly 53.0% of cats were confirmed to be pets living nearby. Cats that were most active in period 1 (≥100 s total activity duration) were classified as ‘residents’; all others were ‘peripherals’.Overall, the ultrasonic deterrents reduced the frequency of incursions into gardens by resident cats by 46%, while the duration of incursions was reduced by 78%. Cat activity declined significantly from period 1 (baseline) to period 2 for resident cats but not peripheral cats (50% reduction; p = 0.001), and remained depressed in period 3 for resident cats but not peripheral cats (p 0.05). Cats confirmed as owned (53% of cats) generated more activity than cats of unknown ownership status (p = 0.03), probably reflecting proximity of their residences to trial gardens. Both deterrent models had similar effects (p = 0.89).By allowing pets to roam, cat owners are complicit in cat nuisance. This requires public education. Ultrasonic deterrents offer a cost-effective, humane option to reduce incursions by unwanted cats. Ultrasonic deterrents will not prevent all incursions, but they reduce their frequency and duration. Reduced cat activity has flow-on benefits to wildlife across a variety of urban-suburban settings, including gardens and parks. Keywords: Cat, Felis catus, Garden, Nuisance activity, Ultrasonic deterrent, Roaming

Domestic cats have a cosmopolitan distribution, commonly residing in urban, suburban and peri-urban environments that are also critical for biodiversity conservation. This study describes the impact of a desexed, free-roaming cat on the behavior of a threatened coastal seabird, the Australian Fairy Tern, Sternula nereis nereis, in Mandurah, south-western Australia. Wildlife cameras and direct observations of cat incursions into the tern colony at night, decapitated carcasses of adult terns, dead, injured or missing tern chicks, and cat tracks and scats around the colony provided strong evidence of cat predation, which led to an initial change in nesting behavior and, ultimately, colony abandonment and the reproductive failure of 111 nests. The death of six breeding terns from the population was a considerable loss for this threatened species and had the potential to limit population growth. This study highlights the significant negative impacts of free-roaming cats on wildlife and the need for monitoring and controlling cats at sites managed for species conservation. It also provides strong evidence against the practice of trap-neuter-release programs and demonstrates that desexed cats can continue to negatively impact wildlife post-release directly through predation, but also indirectly through fundamental changes in prey behavior and a reduction in parental care.

To inform trapping protocols to reduce by-catch while trapping feral cats by-catch welfare costs should be quantified. During cat trapping programs at six Western Australian sites from 1997−2015, 431 non-target individuals, including 232 individuals from native species (132 mammals, 52 birds and 42 reptiles) were captured. Among the native fauna; birds were more likely to be severely injured (33%, compared to 12% in mammals and 21% in reptiles). Amongst other vertebrates, larger individuals were less likely to be injured. Olfactory lures used in these studies attracted reptiles, but repelled mammals. By-catch varied with climate and landscape. Trap injury to by-catch species poses ethical concerns, especially for threatened species that can least afford an additional threat. Future trapping should consider the timing of trapping, trap placement, trap settings (especially the treadle pressure needed to close the trap) and new innovations sending immediate capture alerts to minimise by-catch and potential injury associated with prolonged restraint. By-catch welfare data should be analysed to identify best practice and on-going improvement.

Trap-Neuter-Return (TNR) programs, in which stray cats are captured, neutered and returned to the environment are advocated as a humane, ethical alternative to euthanasia. We review the TNR literature in light of current debate over whether or not there should be further TNR trials in Australia. We revisit the problems arising from stray cats living in association with human habitation and estimate how many stray cats would have to be processed through a scientifically-guided TNR program to avoid high euthanasia rates. We also identify 10 ethical and welfare challenges that have to be addressed: we consider the quality of life for stray cats, where they would live, whether the TNR process itself is stressful, whether TNR cats are vulnerable to injury, parasites and disease, can be medically treated, stray cats’ body condition and diet, and their impacts on people, pet cats, and urban wildlife, especially endemic fauna. We conclude that TNR is unsuitable for Australia in almost all situations because it is unlikely to resolve problems caused by stray cats or meet ethical and welfare challenges. Targeted adoption, early-age desexing, community education initiatives and responsible pet ownership have greater promise to minimize euthanasia, reduce numbers rapidly, and address the identified issues.

Surgical desexing of cats is typically carried out after six months of age (Mature Age Desexing, MAD); between 4–6 months (Traditional Age Desexing, TAD); or before four months (Early Age Desexing, EAD). We complemented existing surveys of veterinarians’ acceptance of EAD with online and face-to-face surveys, to ascertain the preferred desexing ages for cats and rationale of 957 Australian veterinarians, veterinary nurses, veterinary science students, and veterinary nursing students. A complementary survey of 299 veterinary practice websites across Australia documented any information provided about desexing cats. The most common reason for preferred desexing ages was reducing stray cat populations (30%); 78% of these respondents chose ages aligning with EAD. Vet nurses and nursing students were more conservative than vets or vet students, preferring to desex cats >4 months. Perceived anaesthetic risk was a major motivation, especially for nurses ≤5 years’ experience. Across 299 urban practices in Australian capital cities, 55% of surveyed websites provided no information about desexing cats or listed desexing without explaining why it was necessary, or when to perform it. Increasingly, Australian legislatures mandate desexing of cats by three months of age, so the practices of some current/future veterinary professionals do not match changing legislation.

Many healthy adult cats are euthanised annually in shelters, and novel approaches are required to reduce euthanasia rates. Waiving adoption fees is one such approach. However, concerns that less responsible owners will be attracted to free events persist among welfare groups. We evaluated evidence for differences in cat fate, health, and adherence to husbandry legislation via a case-study of a free adoption-drive for cats ≥1 year at a Western Australian shelter. Post-adoption outcomes were compared between free adopters and a control group of normal-fee adopters. The free adoption-drive rehomed 137 cats, increasing average weekly adoptions by 533%. First-time adopters were a significantly larger portion of the free cohort, as a result of mixed-media promotions. Both adopter groups selected cats of similar age; sex and pelage. Post-adoption, both groups retained >90% cats, reporting near identical incidences of medical and behavioural problems. Adopters did not differ in legislative compliance regarding fitting collars, registering cats, or allowing cats to roam. The shelter reported satisfaction with the adoption-drive, because in addition to relieving crowding of healthy adults, adoption of full-fee kittens increased 381%. Overall, we found no evidence for adverse outcomes associated with free adoptions. Shelters should not be dissuaded from occasional free adoption-drives during overflow periods.

As a case study of the responses of natural history museums to changing scientific and funding environments, we analysed research publications of Australia's Natural History Museums (ANHMs) 1981-2020. Using Scopus, 9,923 relevant documents 1981-2020 were identified, mainly research papers but with a growing proportion of reviews. The number of documents published increased over tenfold from 39 (1981) to 553 (2020), likely driven by collaborations (rising from 28.5% of documents 1981-1985 to 87.2% of documents 2016-2020), contributions from retired staff, and volunteer support. The mean length of documents (pages) ranged from a low of 15.3 in 2001-2005 to a high of 17.4 in 1991-1995, but this statistically significant result was trivial in practical terms. The sources (i.e., journals, book titles, conference proceedings) in which ANHM authors published changed over time, with growing proportions of publications in journals covering molecular ecology/phylogenetics and biological conservation. We identified the major areas of study canvassed within the corpus of publications by developing structural topic models based on patterns of word use in document titles, abstracts and keyword lists. The topics discovered included study subjects traditional for natural history museums (new taxa, phylogeny, systematics, animal morphology, palaeontology, minerals), new directions (molecular genetics, ecology, biological conservation) and marine biology (probably reflecting Australia's large coastline). Most citations came from Australia, USA and UK, although in 2016-2020 only 27.9% of citing documents included an Australian author. Growth in numbers of documents and collaborations, as well as use of documents internationally over a period of great change in scientific and funding environments, indicate an enduring legacy of ANHM research, grounded on the intrinsic value of the collections.

International differences in practices and attitudes regarding pet cats' interactions with wildlife were assessed by surveying citizens from at least two cities in Australia, New Zealand, the UK, the USA, China and Japan. Predictions tested were: (i) cat owners would agree less than non-cat owners that cats might threaten wildlife, (ii) cat owners value wildlife less than non-cat owners, (iii) cat owners are less accepting of cat legislation/restrictions than non-owners, and (iv) respondents from regions with high endemic biodiversity (Australia, New Zealand, China and the USA state of Hawaii) would be most concerned about pet cats threatening wildlife. Everywhere non-owners were more likely than owners to agree that pet cats killing wildlife were a problem in cities, towns and rural areas. Agreement amongst non-owners was highest in Australia (95%) and New Zealand (78%) and lowest in the UK (38%). Irrespective of ownership, over 85% of respondents from all countries except China (65%) valued wildlife in cities, towns and rural areas. Non-owners advocated cat legislation more strongly than owners except in Japan. Australian non-owners were the most supportive (88%), followed by Chinese non-owners (80%) and Japanese owners (79.5%). The UK was least supportive (non-owners 43%, owners 25%). Many Australian (62%), New Zealand (51%) and Chinese owners (42%) agreed that pet cats killing wildlife in cities, towns and rural areas was a problem, while Hawaiian owners were similar to the mainland USA (20%). Thus high endemic biodiversity might contribute to attitudes in some, but not all, countries. Husbandry practices varied internationally, with predation highest where fewer cats were confined. Although the risk of wildlife population declines caused by pet cats justifies precautionary action, campaigns based on wildlife protection are unlikely to succeed outside Australia or New Zealand. Restrictions on roaming protect wildlife and benefit cat welfare, so welfare is a better rationale.