Thursday, September 10, 2009

Swan River dolphins

I was sitting on the bus heading back to the university when I saw huge flocks of black birds over the Swan River. I got off the bus hoping to take some photos of the black birds. And I was pleasantly surprised to find that actually those black birds, mainly little black cormorants, were hunting together with a group of four or five dolphins in the river!

I wonder if they are members of the 25 or so "resident" bottlenose dolphins (Tursiops truncatus) that make the Swan River their home. Apparently, dolphin experts can easily tell one dolphin from another simply based on the "distinctive shape" of their dorsal fins or the markings on the dorsal fins (see River dolphins in research spotlight and Bid to trace Swan River dolphin's heritage).

This one is interesting because it has a white mark on its head. I wonder if it's a scar and how the dolphin got it.

The little black cormorants (Phalacrocorax sulcirostris) were busy flying back and forth following the hunting dolphins, joined by a pelican. I saw the pelican fought with a cormorant for fish, with their beaks of course : ) but I was too slow with my camera to capture it.

Most of the black birds were little black cormorants (left), but I also spotted a few pied cormorants (Phalacrocorax varius) (right).

I also saw a male Australasian darter (Anhinga novaehollandiae), which had probably taken part in the hunt for fish.

Watching the dolphins and the huge number of little black cormorants hunting was fun - except for the rain. It was a wet and windy day; but fearing that I might not get a second opportunity to see these animals feeding, I stood there in the drizzle and cold wind watching them for almost an hour. I certainly impressed myself.