Haematological and plasma biochemistry reference intervals for free-ranging Australian pelicans

The aim of this study was to establish haematological and plasma biochemistry reference intervals for free-ranging adult and pre-fledged juvenile Australian pelicans (Pelecanus conspicillatus). These values represent the first species-specific assessments conducted to establish baseline blood values in a wild population of this species. Blood samples were collected from 58 adult pelicans and 53 pre-fledged juveniles between 2018 and 2024 across key sites in the Gippsland Lakes, Victoria, a significant Ramsar wetland for breeding pelicans. Complete blood counts and plasma biochemistry analyses were conducted to characterize reference intervals. White blood cell counts showed heterophils as the most abundant cell type in all age classes. Results revealed significant age-related differences in haematocrit values and plasma chemistry, including urea, total protein and calcium. By interpreting these data within a physiological as well as pathological framework, the study enhances understanding of normal species function and variation across life stages. This study fills a critical gap in understanding pelican physiology and provides essential reference data for wildlife veterinarians, rehabilitators and conservation biologists in the assessment and management of pelican health, facilitating more effective interventions and providing a tool for monitoring broader ecosystem health.