This is a White-Crested Laughing Thrush (sometimes spelled laughingthrush.) It is native to Asian rainforests and the Himalayas. They spend most of their time in the forest canopy.
White-Chested Laughing Thrushes eat seeds, insects, and fruit. Even though the bird is common in its range, it is declining due to habitat loss. They are very social and live in flocks.
I saw this bird in the Reptiles and Birds building at the Brookfield Zoo.