Small urban parks and green spaces, serving as essential recreational venues for city residents, also play a vital and irreplaceable role in maintaining urban biodiversity. It is of great importance to design and plan these areas in a way that integrates multiple habitats for various species while accommodating residents’ usage. This study, carried out at the Futian Mangrove Ecological Park located in Shenzhen, Guangdong Province, China, chose birds as indicator species to assess biodiversity within the park. Site inventory was undertaken from May to September 2022 and from October 2022 to April 2023. We quantitatively described the park’s habitats by examining primary environmental factors, along with 3 primary environmental factors and 11 secondary factors. A correlation analysis was then performed between these factors and bird diversity to gain insights into birds’ habitat preferences across different habitat types and at a finer scale of plant communities. Furthermore, bird clusters in the study case were categorized by foraging guilds and foraging patterns, and their distributions were studied at both the habitat patch scale and the plant community scale. Our findings reveal that, at the habitat patch scale, water surface area and grass coverage significantly positively impact bird diversity. At the plant community scale, plant communities with different structural characteristics vary in their importance to bird clusters with distinct characteristics. In areas with high human disturbance, shrub coverage is crucial for bird habitat protection. Additionally, we discovered that the impact of anthropogenic sound differs among bird species, highlighting the complexity of human disturbance factors on bird habitat preferences. Accordingly, we proposed several design recommendations aimed at enhancing bird diversity in parks, including increasing water body areas, reducing the distance between habitats and water surfaces, enhancing herbaceous plant coverage, and controlling anthropogenic sound.