I was on southern Lamma yesterday (Sok Kwu Wan/Tung O/Mo Tat). Unfortunately I didn't arrive till mid-morning, when it was already hot and sunny, so there could easily have been more birds present.
The obvious highlight of the day was an immature Christmas Island Frigatebird seen drifting over, getting hassled by the local Black Kites (although it didn't seem too concerned!).
Also a good variety of land migrants, including:
Black-naped Oriole
Brown Shrike
2 Asian Brown Flycatchers
2 Common Kestrel
Arctic Warbler
Yellow-browed Warbler
Wryneck
Bright-capped Cisticola (1 or 2 on the hills near Tung O)
2 Cattle Egrets
Striated Heron
At least 3 Blue Rock Thrush
