Great book and my copy is 28 years old. While the book is excellent, it's a bit out of date (1991). Doesn't even include Indian P-H. More and better info, more knowledge, more experienced and accurate reporting, photos, etc all lead to changes in distribution maps, renaming and even "splitting" and "lumping" of species. The most recent and thorough book is the 2018 Lynx Series, Birds of Thailand. It clearly shows Javan P-H in green (bottom left), which indicates Year-round Resident in Phuket. Chinese P-H is a winter visitor in both books. And in winter, which means non-breeding plumage, in the field, the 3 are indistinguishable...except to (maybe) experts. Notice it only shows 1 non-breeding pic for all 3 species. That's how similar they are.