Tai -
Stage 11 of the Lantau Trail begins at Tung Chung Rd - grid reference 047624. Take any New Lantao bus (11, 23, 3M) that goes along Tung Chung Road from Tung Chung to the south of the island. The bus climbs slowly uphill out of Tung Chung and then descends to the South Lantau Road. There is only one stop on the downhill stretch so you can ring the bell on the bus once you're over the crest of the hill. From just ahead of the bus stop, take the steps down to the San Shek Wan catchment and then turn right along the drainage channel for Stage 11 (left for Stage 10 in reverse to Shui Hau - but this is long and not too productive for birds, so not really recommended!)
It's well signposted and pretty straightforward to Pui O, which is about 2.5 km from the start of the walk. The first 1.3 kms is along the catchment channel; the rest is downhill thru shrubland along a dirt trail. The birds I saw were all along the catchment which is quite well-wooded.
Bus timetables can be found at
http://www.newlantaobus.com/nlb.html
Cheers,
David