Editor's note: "Hidden World of Birds in City" is about exploring a world of birds that usually goes unnoticed in urban spaces. This episode features photographs from Wang Xiaobo, who has been bird-watching near his residential community in Beijing for the past eight years.

So far, Wang has recorded 100 species of birds in May this year, the busiest month for birds in a year. Compared to the record of May of last year, which was 105, this year's number doesn't seem quite satisfying, according to Wang. The annual observed species in his community has been on the steady rise over the past five years with slightly over 140 species having been recorded.

More from 'Hidden World of Birds in City':

Hidden World of Birds in City: Small surprises in hot summer

Hidden World of Birds in City: Parenting

Hidden World of Birds in City: New life, new hope

Hidden World of Birds in City: Aiming to create a new record high

Hidden World of Birds in City: Peaks ended but migration lingers

Hidden World of Birds in City: New migration peak

Hidden World of Birds in City: Beauty captured on the way

Hidden World of Birds in City: Catching the train of late spring

Hidden World of Birds in City: Welcome back

Hidden World of Birds in City: Birds in blossom

Hidden World of Birds in City: A busy pond

Hidden World of Birds in City: Highlights

Hidden World of Birds in City: Air predators

Hidden World of Birds in City: Migratory birds

Hidden World of Birds in City: The birds awaken

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