Well I don’t know how much you know. All sorts of seabirds could fit. Double size of a Crested Tern fits Gannet and your description of shape fits and nothing
else you wrote rules out Gannet. Young are dark brown, adults mostly pale.
From: Jean Casburn [
Sent: Wednesday, 18 October, 2017 9:31 AM
Subject: [canberrabirds] Mystery birds Green Cape
For anyone who has an inkling can you tell what bird I have seen please?
Four large ? Tern of mostly dark appearance at 7.30am. Overall impression was sharp – sharp wings, long thin sharp looking body.
They came past us with the flow of Crested Tern some distance from the point of Green Cape. In comparison with the Crested Tern their size was about twice as large as the Crested Tern.
Their flight was very rapid and strong in a south easterly direction away from the shore line.
I watched until they were out of sight.
At the time we saw these birds the stream of Short-tailed Shearwater was thinning but whale activity was plentiful.
I love a mystery.