This report describes the derivation of species-specific relative weights for 25 wild bird species evaluated for inclusion in the Bird Flu Radar, a spatio-temporal risk assessment tool developed by the European Food Safety Authority (EFSA) to estimate the probability of highly pathogenic avian influenza (HPAI) outbreaks in wild bird populations across Europe. The model currently assumes equal parameter values across species, despite evidence of epidemiological heterogeneity. To address this limitation, three key parameters were considered: mortality rate due to HPAI, HPAI prevalence at population level during outbreaks, and HPAI transmission rate to other wild birds. A literature review was conducted to collect available epidemiological data for the selected species, including both peer-reviewed articles and grey literature. Due to substantial data gaps and variability in the evidence, an Expert Knowledge Elicitation (EKE) was performed with four European experts in ornithology and avian influenza. A best–worst scaling (BWS) approach, combined with hierarchical Bayes modelling, was used to quantify relative differences between species for each parameter based on repeated comparative judgments. Results indicated clear differences between species, particularly among waterfowl, which were consistently ranked higher across parameters. These species-specific weights provide a refined representation of epidemiological differences and can be directly integrated into the Bird Flu Radar model. Despite limitations related to data availability and expert uncertainty, this approach offers a transparent and robust framework to improve risk assessment of HPAI in wild bird populations.