Not a common bird but very conspicuous at higher altitudes. Was snowing when we saw it at ~2500 metres ASL. Will perch high on a coniferous tree, looking like a large crow. Said to be ‘silent outside breeding season, but quite vocal from late winter onwards …’ (Handbook of the Birds of the World Alive), but we found it quite vocal in late December. I did not hear the whistles or mimicry calls but managed to document the harsh ‘zhree-zhree’ (Brazil 2009) and an odd buzzing call. Calls are given in a series. A very limited (poor) video of the bird and calls here: http://youtu.be/EXpK4GZ90WY
The N. c. owstoni in Taiwan are darker and have less white spotting and steaks on the breast than the mainland species.
Nutcrackers are credited with planting new trees, especially pine, in view of their habit of storing surplus seed for use later. But I am not sure of the contribution to re-forestation in Taiwan as the local humans have done a marvellous job.