What is this, Claudia's leaf?

Short-winged tree warbler is a kind of forest beneficial bird, which is a summer migratory bird in eastern Anhui. According to the observation in Huangfushan area in eastern Anhui, this kind of bird is found every year. In early and middle April, they migrated one after another, and most of the nesting areas were located at higher altitudes. In the young Pinus massoniana forest about 100 m, the nests are all built on the sunny side of the slope, and there is no nest in a large area behind.