13 Sept 2021

Hong Kong Southern Waters, 12th Sept 2021

The little bit of success seabirding on 29th August proved encouraging. 

So, on Sunday 12th September 2021 many of the seabirders from two weeks before turned out again at Aberdeen Public Pier at 07:00hrs for more of the same. 

Hong Kong was wedged between two typhoons, and the air seemed hot and still.

This time there were no dolphins, nor any Storm-Petrels to be seen. There was a passage of terns going on, though, featuring mainly three species. 

Greater Crested Terns (Thalasseus bergii) were dispersing southwards from their breeding grounds in Fujian/Zhejiang with a few juveniles present. 

Great Crested Tern

Great Crested Tern

Great Crested Terns - juvenile on left, obviously

Great Crested Tern

All morning we encountered both Common Terns (Sterna hirundo) and Aleutian Terns (Onychoprion aleuticus). In bright, hazy conditions, when in flight, they could be hard to separate.

Common Tern

Aleutian Tern - note dark trailing edge to secondaries

Standing on bits of floating polystyrene, identification was more straight forward.

Common Tern

Common Tern - note pink legs, dark edge to carpals 

Aleutian Tern - still mostly adult plumage

Aleutian Tern - still mostly adult plumage

Back to Common Tern (Sterna hirundo), five flight shots......

A quick (five shots) comparison with Aleutian Terns (Onychoprion aleuticus)

Some of these birds are going into winter plumage quicker than others.

Although over 300 individual terns were tallied during the seven-hour trip, not a single skua was spotted.

Finally, there were flocks of egrets moving generally southwest over the sea, clearly more “visible migration” was happening with land birds, too.