The white partridge is widely distributed across northern regions, primarily inhabiting shrub-dominated environments. During winter, its diet is restricted to the shoots of willow and birch; consequently, the bird’s digestive system is uniquely adapted for the digestion of coarse plant material, facilitated by specific anatomical features of the gastrointestinal tract. This study ainmed to investigate the gastrointestinal microbiome of the white partridge during the winter period. The study objects included contents from the goiter, jejunum, ileum, and cecum. Analysis was performed via real-time PCR using the Colonoflor Premium test system. The results revealed the presence of bacteria with cellulolytic and antagonistic activities, such as Bacteroides spp., Blautia spp., Roseburia inulinivorans , and Faecalibacterium prausnitzii . Bacteroides were the most abundant group, with concentrations in the ceca ranging from 3.0 × 10 11 to 4.0 × 10 11 GE/g, while concentrations in the jejunum and ileum were 1.0 × 10 7 –9.0 × 10 7 GE/g and 7.0 × 10 7 –1.0 × 10 8 GE/g, respectively. Roseburia inulinivorans was primarily detected in the cecal contents, with concentrations between 3.0 × 106 and 2.0 × 10 7 GE/g. Faecalibacterium prausnitzii was identified in the goiter (1.0 × 10 5 –4.0 × 10 5 GE/g) as well as in the jejunum and ileum (approximately 2.0 × 10 6 GE/g). The concentration of Bifidobacterium species across various gastrointestinal sections ranged from 1.0 × 10 7 to 8.0 × 10 10 GE/g, and Lactobacillus from 1.0 × 10 7 to 4.0 × 10 7 GE/g. Among methanogens, Methanobrevibacter smithii was not detected, whereas Methanosphaera stadtmanae was identified exclusively in the ceca at levels of 9.0 × 10 7 –6.0 × 10 8 GE/g. The opportunistic microflora was represented by the genera Acinetobacter , Escherichia , Enterobacter , Enterococcus , and Staphylococcus . The identified symbiotic microorganisms are of significant scientific interest and may serve as producer strains for the development of enzymatic and probiotic agents.