A standardized and flexible method for prioritizing and integrating several dimensions of the conservation value of species was developed and applied to breeding birds (131 species) throughout a French administrative unit: the “département” of Ille-et-Vilaine (35). The methodology is based on three criteria commonly used to assess the value of preservation: species vulnerability, rarity and biological (phylogenetic and functional) originality. These criteria are described by nine complementary indicators provided as continuous or discrete variables. The computational principle of the index is based on scoring, which distributes the values of the indicators of each criterion into five increasing categories of scores. Using the weighted average of the values of each indicator, we assigned an overall score to each species, which evaluated the preservation value in a continuous manner – preservation values of bird species at the “departmental” level – and compared it with conservation values of species at the regional level. The preservation value index (PVI) is a limited and flexible multi-criteria integration index applicable to other taxa regardless of the evaluation method developed for the indicators and whatever the indicators selected. It can be used routinely for quick updates and to standardize comparisons across different administrative territories at multiple scales including sub-national levels.