Yes, more observations.... both land based and sea trips. Some birders are pioneers in this aspect. Now, owing to their hard work, we know more seabirds but still have some gaps...
Here is a quick summary around HK and northern South China Sea
Jan - Feb: ???
late Mar: streaked shearwater / skua
Apr - May: tropicbird, bobbies (red-footed + Brown), Leach's storm-petrel, + terns + short-tailed shearwater + skua + Bulwer's Petrel
Jun - Jul: short-tailed Shearwater + skua + Lesser frigatebird + 3 breeding terns
Aug: Gr Crested Tern + Aleutian Terns + 3 breeding terns + Swinhoe's Storm-petrel + Lesser frigatebird
Sept: streaked shearwater + Swinhoe's storm-petrel + migratory terns + Skua + Boobies + Wedge-tailed Shearwater
Oct - Dec: ??? (Ancient Murrelet?)
