| Garden plants provide important food resources for urban birds, and the configuration of garden plants will affect the species, number and community structure of birds in the city. The study on the relationship between urban birds and food plants can clarify the feeding relationship between birds and food plants and provide technical support for improving the diversity of urban birds. From 2017 to 2019, the species and quantity of food plants eaten by birds in Beijing were recorded by direct observation and field photo recognition. Six research sites were selected, and one transversal line was set for each study site. The length of transversal line was 2.52 km in Old Summer Palace, 3.12 km in The Summer Palace, 3.02 km in Beijing Botanical Garden, 2.76 km in Olympic Forest Park, 1.38 km in Beijing Forestry University and 1.6 km in Beijing Language and Culture University. A total of 49 species of plant-feeding birds and 56 species of food plants were recorded. The plants that attract the most bird species are Lonicera maackii, followed by Sabina chinensis, Diospyros kaki, Pinus tabuliformis, Ulmus pumila, etc., and the birds that feed on the most plant species are Azure-winged Magpie (Cyanopica cyana), followed by Light-vented Bulbul (Pycnonotus sinensis), Eurasian Tree Sparrow (Passer montanus), Brambling (Fringilla montifringilla), Oriental Magpie (Pica pica) and so on. The garden plants that attract the highest diversity of birds are L. maackii, D. kaki, Pinus tabuliformis, Ginkgo biloba, Populus tomentosa, etc., and the birds that feed on the highest diversity are Azure-winged Magpie, Light-vented Bulbul, Eurasian Tree Sparrow, Brambling, Oriental Magpie and so on. Birds feed on the source plants from October to May of the following year, and the peak period is from November to December, in which the peak of berry feeding is from November to December, the peak of eating nuts is from November to January of the following year, the peak of feeding on leaf buds is from November to December to March to April of the following year, and the peak of feeding on flowers is from March to April. The seasonality of birds feeding on food source plants in Beijing is obvious, so it is necessary to increase the proportion of garden plants that can provide food for birds for a long time in winter, such as Sabina vulgaris, Platycladus orientalis and other food resources to provide sufficient food resources for birds in late winter and early spring.
As important food resources for birds living in cities, the assemblage of ornamental plants in gardens and parks plays a significant role in species composition and abundance of urban bird communities. Understanding the relationship between urban birds and edible plants can provide technical support for conservation of urban birds diversity, but remains poorly studied. From 2017 to 2019, species and abundance of plants that birds forage on were recorded in multiple sites in Beijing, by direct observation and field photo identification. The diversities of birds and plants were calculated using Shannon index, and the niche widths were calculated by Levins (1968) model. The chi - square test was used to assess the differences in the type of food that birds forage on among months. A total of 49 species of birds foraging on 56 species of plants were recorded. The plant foraged by most bird species was L. maackii, followed by S. chinensis, D. kaki, Pinus tabuliformis, U. pumila, etc. Among the bird species, Azure-winged Magpie, was recorded foraging on most plant species followed by Light-vented Bulbul, Eurasian Tree Sparrow, Brambling, Common Magpie (Pica pica), etc (Fig. 1). Plant-foraging in birds was concentrated from October to the following May, and peaked in November and December (Fig. 2), among which the main food resources change across months. Berries were mostly foraged from November to December, nuts from November to the following January, leaf buds from November to December and March to April, and the peak of flower-foraging occur from March to April (Fig. 3). Among the recorded plants, S. chinensis and Platycladus orientalis served as the main food resource for a long time in winter. Therefore, in order to increase number of birds in Beijing, the proportions of these plants should be increased to provide sufficient food resources in late winter and early spring when food resources are most scarce. |
