Abstract:[Objectives] China is one of the megadiverse countries with the largest diversity of birds, and the biodiversity in China is facing threats from rapid urbanization and population growth. There are large conservation gaps in eastern China, where most of the populous cities are located. The Yanshan Mountains range is located in the priority area of biodiversity protection, and close to the densely populated Beijing-Tianjin-Hebei urban agglomeration, with a high diversity of bird species, however, the distribution patterns and conservation status of national key protected birds in the Yanshan Mountains are still unclear. [Methods] In this study, we used FRAGSTATS (version 4.2) to quantify the landscape pattern of habitats in Yanshan Mountains (Fig. 1) using 5 commonly used parameters and selected 40 national key protected birds as indicators (Fig. 2a) to assess the local habitat and biodiversity protection status. We produced species distribution models for every indicator species using a maximum entropy approach. Marxan was used as an effective method of planning protection units that consider conservation cost of different land use on the basis of the indicator species’ potential distribution. [Results] We found that the forest habitat in Yanshan Mountains has the largest proportion (61.5%) with a total of 6 537 km2 (Fig. 2b) and the least fragmentation (Table 1). Grassland habitat was 1 910 km2, accounting for 18.0%. Agricultural land is 1 438 km2, accounting for 13.5%. The wetland habitat is only 345 km2, accounting for 3.3% (Fig. 2c), including Guanting Reservoir, Miyun Reservoir, Huairou Reservoir and other large water bodies. The area of national nature reserve in Yanshan Mountains is 404 km2, 94.6% of which is forest and grassland, while the area of wetland habitat is very small. Forest-Grassland type is the representative habitat in Yanshan Mountains, occupying the majority of habitats and having good connectivity (Table 1). The patch density of wetland is very low with a high degree of dispersion between patches, resulting in further decrease of connectivity. However, it can be seen from (Fig. 2a) that the diversity of the national key protected birds in wetland habitats is similar to that in forest habitats, and the number of wild birds under national first-class key protection is the largest, indicating the importance of wetland habitat types to biodiversity in Yanshan Mountains. The species distribution model predicted that areas with high biodiversity tended to be around water habitats such as Miyun Reservoir, Guanting Reservoir and Yuqiao Reservoir (Fig. 3a), while very small in forest habitats and there were biodiversity hotspots around Yanqing District. Distance from lakes contributes greatly to the simulation of potential distribution areas, especially in the modeling of wetland birds (Appendix 2). Based on Marxan analysis, the optimal solutions of 2 442 km2 of biodiversity hotspots requiring priority conservation were identified (Fig. 3b) with the original national nature reserves accounting for 16.5% of the hotspots. Totally, 33 species reached the conservation target (Appendix 3), with the average protected percentage of the potential distribution increasing from 1.2% to 33.6%. The proportion of forest and grassland in the biodiversity hotspots is 72.3% and 15.2%, respectively. Totally, 56.3% of the total area of wetland in Yanshan Mountains is included in the hotspot areas (196 km2), accounting for 7.9% (Fig. 3c), strengthening the protection of reservoir and other wetland environments. The number of species in every 1 km × 1 km raster of the biodiversity hotspot for prioritized protection in the forest, wetland and farmland are higher than in the overall range of Yanshan Mountains (Fig. 4), showing the hotspot areas were able to cover the major distribution hotspot of the national key protected birds. The habitat in the biodiversity hotspot requiring prioritized protection identified by the Marxan model is more equalized and diversified, with higher conservation efficiency, compared with the existing national nature reserves. [Conclusion] The protected areas of national nature reserves in Yanshan Mountains present a huge conservation gap of wetland habitat, indicating that the construction of more coherent protected areas in this area is of great significance to the protection of national key protected birds in highly urbanized areas. Areas of high landscape heterogeneity exhibited higher biodiversity but a lower proportion of protection with the need for more thorough field investigation. Our approach of conservation gap analysis for threatened birds on a multi-species and multi-habitat scale will be helpful for future conservation planning in densely populated areas.