I know this thread is a little old, but I just wanted to throw in my two cents.
First off, I just got back from a 3 day trip to Kending with the Wild Bird Society of Taipei, and they are a great organization. The entire trip cost $6200 NT, and included all travel from taipei, all food, two nights (shared room) at a nice hotel in Kending, and all guiding. 71 species including two endangered species were counted on the trip. Although the English is very limited, people are very friendly, and the few that do speak English will go out of their way to help. If you would like more information, you can email them, or PM me and I will give you some additional contact info.
Also, just wanted to throw out there that if anyone is interested in doing some bird-watching in the Taipei area, I go rather regularly, and am always keen to have company. PM me if you'd like. Taiwan has the second highest concentration of bird species per km of any country in the world, its a shame to miss out on it.