*Article* **Identifying the Stressors Impacting Rescued Avian Wildlife**

#### **Kimberley Janssen 1, Crystal Marsland 1, Michelle Orietta Barreto 2, Renae Charalambous 1,3 and Edward Narayan 1,3,4,\***


Received: 6 July 2020; Accepted: 24 August 2020; Published: 25 August 2020

**Simple Summary:** Stress evaluation in wildlife is valuable tool for rehabilitation and injury prevention. This pilot study investigated categories of stress in rescued birds. We determined three categories of stressors (preliminary, primary and secondary) using clinical data of rescued birds from Adelaide, South Australia. It was discovered that birds are highly susceptible to impact injuries (e.g., flying into a building window) and vehicle-related injuries as preliminary stressors, which often result in hospitalisation of birds. Immobility and abnormal behaviour represented the most common primary stressor, while the most common secondary stressors included trauma and fracture. Furthermore, the most common outcome in clinics due to exposure of birds to these three stressor categories was euthanasia.

**Abstract:** Urbanisation exposes avian wildlife to an array of environmental stressors that result in clinical admission and hospitalisation. The aim of this pilot study was to conduct a retrospective analysis of clinical data and characterise this based on categories of stress experienced by avian wildlife patients. The results from this study indicated that impact injuries (*n* = 33, 25%) and vehicle-related injuries (*n* = 33, 25%) were the most common occurring preliminary stressors that resulted in the hospitalisation of avian wildlife. The most common outcome of avian patients that suffered from vehicle-related injuries was euthanasia (*n* = 15, 45%), as was avian patients that suffered from impact injuries (*n* = 16, 48%). Immobility (*n* = 105, 61%) and abnormal behaviour (*n* = 24, 14%) were the most commonly occurring primary stressors of avian patients. Finally, trauma (*n* = 51, 32%) and fractures (*n* = 44, 27%) were the most common occurring secondary stressors in avian patients. The most common outcome of all these stressors was euthanasia. This study provided further evidence towards the notion that human- and urbanisation-related stressors are the main causes of hospitalisation of avian wildlife, but also indicated that birds admitted as a result of human-related stressors are more likely to be euthanised than released. This study also provided a categorisation system for the stressors identified in avian wildlife patients (preliminary, primary and secondary) that may be used to monitor the stress categories of wildlife patients and gain a deeper understanding of the complex notion of stress.

**Keywords:** wildlife; environmental stress; urbanisation; birds
