I would totally agree. Province like Guangzhou has a great weather of enabling wildlife, mild winter and rainy summer. I was amazed when I first arrived in China, I hardly see any Eurasian Tree Sparrow in town, they are the most common bird species in this part of Asia. Bulbul and starling are extremely rare in city parks, partly due to lack of green at the area surrounding the park. Ecosystem at the park alone is not sufficient to sustain bird polulation.
Besides large scale habitat loss, there is a lack of respect for wildlife. Majority of locals still think that wildlife is still plentiful. Lack of support from the government may also be the reason why common birds are not common anymore.