Do any friends who know birds know what kind of bird this is?

White-backed bird (scientific name: Lonchura striata), common name: Li Bai bird, Hegu, ten sisters, ten sisters, fortune-telling bird, belonging to the genus Spartina. Often more than ten people live together in the old nest, so they are called ten sisters. The body length is about11mm. The waist is white and the belly skin is yellow and white. There are white longitudinal stripes on the back and tiny yellowish scaly spots and fine lines on the lower body. Sex is noisy, and they live a small group life. Habits like other wenbirds. The white-waisted wenbird is rich in population. At the maturity of grain, people often fly to the farmland in droves to peck at grain, which brings certain harm to agriculture.

Note: Image source: Oriental Bird Society image database.