I have photographed Black Bulbul before many times. They are not rare around Taipei. I was at Wulai (烏來) hoping to see some exotic birds. All I could hear was a lot of bird noise. I finally realized it was from a whole group of black bulbul. They flied back and forth between two sides of the valley. I sat down to rest and suddenly they came right in front of me. This is certainly rare to see so many of them on the same tree, all in the same focal plane and on leaves to obscure the birds.
