Hospital admissions to Phillip Island Wildlife Clinic, Victoria, Australia, over a 10-year period, 2012–2021

ABSTRACT Wildlife clinics play a critical role in safeguarding the well-being and survival of diverse animal species, but their admissions data are also valuable for investigating threats and challenges impacting local wildlife. This study examines 10 years of admissions data from the Phillip Island Wildlife Clinic in Victoria, Australia, to identify species, primary causes, outcomes, and temporal trends of clinic admissions. Avian species constitute the majority of admissions (64.5%), with sea and water birds being the most frequently admitted group. Motor vehicle accidents, injuries of unknown cause, and orphaning are the dominant causes of admission for birds and mammals. Car strikes are the leading cause of admission for land birds, land mammals, macropods, and turtles. Orphaning exhibits a seasonal pattern, with a higher number of cases in spring. Overall, 59.1% of admissions resulted in mortality, with causes related to trauma showing significantly higher mortality risks than others. The findings emphasise the impact of tourism on wildlife populations and the urgent need for targeted conservation strategies on Phillip Island.


Introduction
Wildlife clinics play a pivotal role in safeguarding the well-being and survival of rescued wildlife.By evaluating longitudinal admissions data from these facilities, a valuable opportunity arises to investigate the threats and challenges that impact the well-being of local species.This analysis not only enhances our understanding of these risks but also provides valuable insights to inform conservation strategies aimed at protecting and preserving wildlife, particularly vulnerable populations (Pyke and Szabo 2018).
Previous studies have provided valuable insights into wildlife clinic admissions and mortality rates across different regions of Australia.For instance, research conducted in south-east Queensland (SEQLD) revealed that marsupials accounted for the largest proportion of admissions (41.3%) (Taylor-Brown et al. 2019).The primary reasons for admission included car strikes (34.7%), orphaned young (24.6%), and overt signs of disease (9.7%) (Taylor-Brown et al. 2019).Studies in New South Wales (NSW) have also reported on wildlife clinic admissions, with avian species being the most commonly admitted taxa (Tribe and Brown 2000;Haering et al. 2021;Kwok et al. 2021).Similarly, a study investigating wildlife admissions to domestic animal veterinary clinics (n = 132) across Australia reported that birds were the most commonly admitted taxa (Orr and Tribe 2018).In agreement with Taylor-Brown et al. (2019), these studies also highlight car strikes as a leading cause of admission (Orr and Tribe 2018;Tribe and Brown 2000;Haering et al. 2021).Overall, the reported mortality rate across these studies is approximately 55% (Taylor-Brown et al. 2019;Tribe and Brown 2000;Haering et al. 2021;Kwok et al. 2021).However, mortality rates in sick and injured wildlife vary depending on the nature of the impact.For example, reported mortality rates in macropods from vehicle strike are much higher than 55%, at or approaching 90% (Taylor-Brown et al. 2019;Kwok et al. 2021).
Several studies have focused on individual species, such as the flying fox in Victoria (Scheelings 2015) and New South Wales (Mo et al. 2021), where entanglements have been identified as the primary cause of admission.Scheelings (2015) found a significant proportion of flying fox admissions were attributed to entanglements in fruit netting (36.8%), resulting in considerable mortality of up to 56.1%.For freshwater turtles in SEQLD, trauma, predominantly resulting from car strikes, emerged as the most common cause of admission (O'Leary et al. 2023).However, over the study period, an increasing number of turtles presented with disease (O' Leary et al. 2023).
Koalas have also received considerable attention in this area of research, particularly in NSW.Lunney et al. (2023) conducted an extensive examination of 18,039 koala admission records from NSW rehabilitation groups spanning 47 years.Their findings highlighted disease as a prevalent factor in koala admissions, accompanied by motor vehicle collisions, dog attacks, and instances of unsuitable environments.A parallel study conducted in Lismore (south-east NSW) over 31 years, exploring 5051 koala admissions, reaffirmed these results, emphasising the significant impact of disease, unsuitable environments, and dog attacks (Lunney et al. 2022).Furthermore, an additional analysis in Port Macquarie over a 30-year period identified motor vehicle collisions, dog attacks, and disease as notable contributors to koala admissions (Griffith et al. 2013).These findings align with studies conducted in other regions across Australia, which similarly highlight trauma (e.g.motor vehicle collisions, dog attack) and disease as common factors leading to koala admissions (Gonzalez-Astudillo et al. 2017;Charalambous and Narayan 2020).Together, these previous findings underscore the significant impact of human activities on a diverse range of wildlife, and the significant influence of disease.They also emphasise the urgent need for continued research and conservation efforts to protect Australia's iconic native species.
Located on a relatively small land area of 101 km 2 , Phillip Island serves as a holiday destination for tourists.The island's popularity, however, increases the likelihood of humanwildlife interactions that can result in conflicts and incidents leading to animal injuries.To address these challenges, the Phillip Island Wildlife Clinic (PIWC; a registered wildlife shelter, utilising external registered veterinarians, both on and off-site) plays a crucial role in serving the wildlife population of the island.By thoroughly examining the nature and circumstances surrounding admissions at the clinic, this study has the potential to raise awareness among tourists and local communities, fostering a sense of responsibility and promoting wildlife conservation practices.Moreover, by gaining insights into these admissions, the study enables the development of informed strategies and interventions aimed at mitigating these risks and minimising their impact on the island's unique biodiversity.
Here I present the results of a 10-year analysis of data collected from the PIWC.The objectives of this study were to identify which species are being admitted to PIWC, in addition to the primary causes, outcomes, and temporal trends of clinic admissions to determine and quantify the current threats to their survival in this region.

Study site and data collection
The wildlife clinic admission records used in this study were obtained from the Phillip Island Wildlife Clinic (PIWC) (−38.470321°, 145.367326°)Clinic admission records of 3842 wildlife patients admitted by members of the public to PIWC between 1 January 2012 and 30 December 2021 were compiled in an electronic database (Microsoft Excel,ver. 16.73) for organisation and analysis.Information contained in the records included: patient identification number, admission date, species, age category, cause of admission (COA), and outcome; although sex was included in the clinic records, data were not recorded consistently and were therefore not included in the analysis.Of the 3842 cases, 473 were excluded as follows: (a) nonnative species, (b) incomplete records, and (c) species for which there were fewer than 50 individuals, unless they could be suitably pooled with species of another taxonomic, ecological or behavioural group.Given the significant number of species across taxonomic groups with fewer than 50 individuals, nine multispecies groups were formed based on taxonomic or ecological similarity.These groups encompassed sea and water birds, terrestrial birds, arboreal mammals, terrestrial mammals (excluding macropods), macropods, bats, turtles, and lizards.
These data were analysed for admission and outcome trends.Where trends were assessed per season, seasons were referred to as: summer (December, January, February), autumn (March, April, May), winter (June, July, August), and spring (September, October, November).COA, as determined by the attending veterinarian was used as a nominal outcome variable with 15 categories: 'caught accidentally' (e.g.chimney, building, drain, pool), 'caught in fishing line', 'unnecessary rescue' (i.e.animals were brought into the clinic by members of the public but were determined to be healthy by the veterinarian), 'unknown animal attack', 'dog attack', 'cat attack', 'disease', 'exhausted', 'orphaned', 'collision' (e.g.pole, wire fence, overhead wires, window), 'motor vehicle accident' (MVA), 'injury', 'paralysis', 'malnourished', and 'other' (causes of admission with fewer than 20 entries).Animal outcomes following admission were grouped into either 'positive outcome' (released into wild or into care) or 'mortality' (dead on arrival, natural death, or euthanasia on welfare grounds).Phillip Island human population data were obtained from the Australian Bureau of Statistics (2021).

Statistical analysis
Statistical analysis was performed using 'R', ver.2022.12.0 + 353 and Prism, ver.9.5.1.Descriptive statistics were used to determine the frequency of cases for each season, diagnosis, and outcome during the study period.Linear regression was used to explore temporal trends, including total number of admissions and diagnoses.One-way ANOVA was performed to compare the average number of cases by season, utilising Tukey's post hoc analysis to explore pair-wise comparisons and investigate significant relationships.Finally, logistic regression was used to produce odds and risk ratios with 95% confidence intervals.

Discussion
This study presents a comprehensive analysis of 10 years of wildlife clinic admission data from PIWC.It builds upon an increasing understanding of the factors contributing to Australian native wildlife clinic admissions and their chances of survival.The findings reveal several key points: (1) birds are the most common animal group represented in the admissions, followed by mammals; (2) the dominant causes of admission for birds and mammals are MVAs, injuries of unknown cause, and orphaning; (3) seasonal trends in clinic admissions are observed; and, (4) causes of admission related to trauma have higher mortality rates for wildlife than other cases such as 'caught accidentally' or 'orphaned'.Overall, these results offer valuable insights into the challenges faced by Philip Island wildlife and emphasise the importance of targeted conservation strategies and interventions.
The findings of this study revealed that avian species constituted the majority of wildlife admitted to PIWC, accounting for 64.5% of all admissions, with sea and water birds the most frequently admitted bird group (59% of all birds).These findings align with previous reports from private veterinary clinics across Australia (Orr and Tribe 2018) as well as rehabilitators (Tribe and Brown 2000;Kwok et al. 2021) and a private veterinary clinic (Haering et al. 2021) in NSW, but differ from reports in SEQLD (Taylor-Brown et al. 2019) and Victoria (Tribe and Brown 2000), which observed higher admissions for mammalian species.
The high admissions of species observed in the present study is likely influenced by the unique geographical and ecological characteristics of Phillip Island.The island's location off the southern coast of Victoria provides access to diverse coastal ecosystems and habitats that offer favourable conditions for a variety of bird species, especially sea and water birds, which rely on these areas for feeding, nesting, and roosting.Further, Phillip Island serves as an important migratory pathway for many bird species, including shearwaters (the most admitted species in this study), using it as a stopover or wintering site (Phillip Island Nature Parks 2023).
The popularity of Phillip Island as a tourist destination and its associated ecotourism activities may also contribute to the high proportion of avian species admitted to PIWC.The island attracts a substantial and increasing number of visitors each year (Department of Jobs, Skills, Industry and Regions 2023), leading to increased traffic flow.This influx of vehicles on the island's roads not only raises the likelihood of MVAs involving avians and other wildlife groups, but also enhances the opportunities for human-wildlife interactions.Specifically, sea and water birds, being present near coastal areas and popular tourist sites may come into closer proximity to humans.Unfortunately, these interactions can result in potential disturbance to wildlife, including distress, accidental injuries, entanglements, or disturbances to nesting sites (Carney and Sydeman 1999;Guillemain et al. 2007;Shannon et al. 2017).Further, unnecessary rescue was a major cause of admission in this study, particularly for birds, highlighting the need for public education initiatives to reduce admissions due to this cause.Implementing strategic measures, such as placing infographics in coastal areas and popular tourist sites, offering a comprehensive list of indicators for appropriate rescues, or encouraging individuals to contact the clinic for initial assessment, could effectively alleviate stress on the clinic and ensure more efficient care for the animals.
The increasing human residency on Phillip Island over the last 10 years has likely intensified the human-wildlife interface with urban development and expansion encroaching upon natural habitats resulting in habitat fragmentation and potential population density challenges for wildlife.This increased population, coupled with high motor vehicle density, may lead to car strikes as the leading cause of animal admissions on Phillip Island.Specifically, car strikes are the primary cause of admission for land birds, land mammals, macropods and turtles and the second-highest cause for sea and water birds and arboreal mammals.This finding is consistent with previous studies conducted across Australia, which have identified car strikes as a significant threat to various species including birds, reptiles, amphibians (Scheelings 2015;Taylor-Brown et al. 2019;Kwok et al. 2021;O'Leary et al. 2023) and koalas (Griffiths et al. 2013;Gonzalez-Astudillo et al. 2017;Charalambous and Narayan 2020;Lunney et al. 2022Lunney et al. , 2023)).Given the substantial and escalating impact of car strikes on the native wildlife of Phillip Island, it is recommended that local councils take proactive steps, including maintaining roadside vegetation, reducing speed limits, and installing flight deflectors along roadsides to encourage birds to fly above vehicle height (Loss et al. 2014;Shilling and Waetjen 2015).Additional measures to be considered involve the implementation of management efforts such as wildlife underpasses and overpasses across roads with fencing.These initiatives would not only enhance the safety of wildlife but also contribute to human well-being, as collisions between vehicles and wildlife can lead to a significant number of human injuries and substantial damage to vehicles (Gunson et al. 2011;Loss et al. 2014;Shilling and Waetjen 2015).
Orphaning was another significant cause of admission across various species, including arboreal mammals, water birds, and macropods.These admissions exhibited a clear seasonal pattern, with a considerably higher number of cases during spring compared to other seasons.Similarly, all other causes of admission demonstrated a seasonal trend, with significantly lower numbers during winter in comparison to other seasons.This seasonal fluctuation is observed consistently across Australia (Heathcote et al. 2019;Taylor-Brown et al. 2019;Tribe and Brown 2000;Kwok et al. 2021) and can be attributed to several factors, including increased activity associated with breeding and rearing of young, as well as greater movement and activity of animals during the warmer spring and summer months.Although there was an overall increase in total number of admissions when comparing 2011 and 2021, for six of the 10 years, admission rates appear to be lower than baseline ( 2011).This may be attributed to a combination of factors, including natural population fluctuations, stabilised public reporting patterns following an initial surge in awareness in 2011, and potential improvements in wildlife health due to shifts in food availability and predator-prey dynamics.
The most numerous species admitted were swamp wallabies, possums, short-tail shearwaters and Cape Barren geese, species currently of no conservation concern.In some cases, particularly for mammals, the high admission numbers of these species may, in part, be attributed to population density issues on the island, where wildlife may face challenges in relocating to other areas.Five endangered species were admitted throughout the study period.Of particular interest is the eastern barred bandicoot, which was introduced to Phillip Island in 2017 as part of a strategic initiative to rescue the species from extinction (Department of the Environment, Land, Water and Planning 2021).The clinic has observed 12 admissions between 2018 and 2021, with seven cases attributed to unknown causes.Addressing the unknown causes of admission for this species is important for a comprehensive understanding of the threats they face on the island.Further, collecting more data for such species through rescue, recovery, and release efforts can contribute significantly to their conservation by providing insights into risk relative to various causes of admission, location, time of year, sex, and age.This datadriven approach can enhance our understanding of the ecology of endangered and vulnerable animals, contributing valuable information for their management and conservation (Pyke and Szabo 2018).
The average rate of mortality across all admission types for all animals admitted was 59.1%, slightly higher than reported in previous Australian studies with documented mortality rates of 55.2% (Kwok et al. 2021) and53.6% (Taylor-Brown et al. 2019) across diverse species and causes of admission.However, mortality rates exhibit considerable variation among different species and causes of admission across these studies.For example, macropods consistently show mortality rates approaching or exceeding 90% in car strike incidents (Taylor-Brown et al. 2019;Kwok et al. 2021), and avian species have shown mortality rates between 67% and 86%, depending on species (Orr and Tribe 2018;Taylor-Brown et al. 2019;Kwok et al. 2021).Conversely, turtle species have greater survivability following car strike with mortality rates of 41.7% (present study), 37.7% (O'Leary et al. 2023) and56.6% (Taylor-Brown et al. 2019).In the present study, mortality rates associated with 'caught accidentally' were generally below 22% across species.However, mortality rates were notably high for macropods, terrestrial birds, and lizards when compared to other species groupings.This observation highlights the importance of educating and communicating information to the general public, including pool safety measures such as adding exit points and providing climbing opportunities for wildlife near drains and buildings and other hazards wildlife may encounter.Finally, 'malnourished' emerged as a relatively common cause of admission, associated with a high mortality rate among arboreal mammals, macropods, terrestrial birds, and sea and water birds.Instances of malnourishment were frequently observed during summer and autumn, although this pattern was not consistently observed across all years.Nonetheless, it may be a consequence of environmental pressures resulting from increasing global temperatures and/or population density strains; regardless, further investigation is warranted.Overall, these findings underscore the urgent need for conservation efforts and targeted interventions to mitigate the impact of tourism and reduce physical trauma incidents among wildlife populations on Phillip Island.

Conclusion
In conclusion, this 10-year analysis of wildlife clinic admissions at the Phillip Island Wildlife Clinic provides valuable insights into the primary causes, outcomes, and temporal trends of wildlife admissions in the region.The notable presence of avian species among the admissions highlights the need to address the specific challenges faced by these populations on Phillip Island.Conservation efforts should prioritise the preservation and restoration of coastal and wetland habitats, as well as the implementation of measures to minimise human-wildlife conflicts.Raising awareness among tourists and local communities about responsible wildlife interactions is also crucial.Additionally, conducting further research on avian ecology, habitat assessments, and migratory patterns specific to Phillip Island can provide detailed insights into the dynamics of avian populations, aiding in the development of targeted conservation strategies.It is anticipated that the findings of this study will contribute to the formulation of targeted conservation strategies, interventions, and public awareness campaigns aimed at mitigating these threats and promoting responsible practices that safeguard the unique biodiversity of Phillip Island for future generations.

Fig. 3 .
Fig. 3. Seasonal animal admission to Phillip Island Wildlife Centre for the top six causes of admission.
located in Phillip Island, Victoria, Australia.Phillip Island is situated 142 km south of Melbourne and encompasses an area of approximately 101 km 2 ; the last census (2021) recorded a population size of 13,799 (Australian Bureau of Statistics 2021).The clinic, established in 2011, forms part of Phillip Island Nature Parks, attracting approximately 2.7 million national and international visitors annually (Department of Jobs, Skills, Industry and Regions 2023).

Table 1 .
Summary of admissions to Phillip Island Wildlife Clinic from 2012 to 2021.Bold text indicates totals and primary causes of admission per group.

Table 2 .
Leading causes of wildlife hospital admissions by species groups.

Table 3 .
Outcomes of the top six causes of admission for each multispecies group.