Little Tern (Sternula albifrons) in mixed tern roost

The Little Tern (Sternula albifrons sinensis) is the tiny tern in the middle. The other terns are mostly White-fronted Terns (Sterna striata). At the left are two non-breeding Caspian Terns (Hydroprogne caspia) and a Red-billed Gull (Chroicocephalus novaehollandiae scopulinus).

Are the brown birds at the back grey teals?

@WalkingAgnatha yes - there were both Mallards and Grey Teal there, but I'm pretty sure the two in the photo are indeed Grey Teal.