Kites - here, the Black-eared kite, very common in Hong Kong.
I know i have posted this text before, but for those who have not read it yet:
A common but wonderful sight on the Peak near the Matilda hospital, or on Sundays in SaiKung off the main pier, are the large birds called Kites that ride the airways above and below the hospital. The forested area of the Peak around the hospital is now among the largest Kite roosts in East Asia.
The Black-eared kite’s specific taxonomy is still being debated by scientists with the evolution of genes of local birds under investigation, so some still call them Black Kites. Partially migratory birds, they prefer the tropics in winter, flying over, unusually for raptors, in large groups over bodies of water.
Research suggests the winter population keeps to around 2-3000 birds, but in the summer only around three hundred or so may choose to stay in Hong Kong. The best time to view them from the Matilda is near the evening as they return to their homes. The main roosting areas are on the forested slopes of the Peak off Magazine Gap Road and Stonecutters Island. Kites that are born here generally remain for a year. As well as eating fish, Kites also feed on birds, snakes, lizards, rodents and carrion. Considered to have strong legs, but weak feet, they are still pirates of the air, occasionally stealing prey from other eagles. They are opportunistic eaters, and we’ve even witnessed one trying to carry off a little boy’s shoe!
Despite living off a mercury laden fish diet, they probably have a similar technique to the Japanese Black-eared kites, where they accumulate the toxins in their feathers, then deposit them by moulting.