Subject: Cormorants between Deep Bay and Starling Inlet 到沙頭角海覓食的鸕鶿 [Print This Page] Author: wcaptain Time: 25/01/2010 15:14 Subject: Cormorants between Deep Bay and Starling Inlet 到沙頭角海覓食的鸕鶿
Just last Sunday (about 10:00 AM 24 Jan 2010), I saw at least two flocks of Great Cormorants (total about 100 birds) left Starling Inlet and flew towards the Fanling drection.
There were about 270 cormorants in Starling Inlet yesterday. Currently there is no wintering roosting site of Cormorants at Starling Inlet but there was such roosting site on A Chau ten yrs ago.
As the presence of roosting sites of Cormorants between Deep Bay and Starling Inlet are highly unlikely, so the Cormorants were supposed to fly towards Deep Bay.
Not sure whether there are such sightings. It is interest to know that Cormorants at Deep Bay could reach Starling Inlet for feeding. The distance apart is about 20 km. Probably takes about half hour each way.
Mike and I saw such Cormorant flock at Lin Ma Hang in 2004 but not 100% sure the destination.
The tide was high at that time when they left Starling Inlet. It is reasonable to guess that they left Deep Bay at dawn and then return to Deep Bay when the tide at Starling Inlet was tide. So, they may have had about 4 hrs to feed at Starling Inlet.
Questions about this sighting are
1. why these Cormorants did not stay at Deep Bay to feed? reduce competition with other wintering Cormorants? What is the trigger level? i.e. when wintering population reaches to certain number of birds, some will travel to Starling Inlet
2. why they don't stay at Starling Inlet? Not enough food to allow establishment of a wintering pop at Starling Inlet?
3. How often did they travel to Starling Inlet? Every day? or just early morning low tide in Starling Inlet?
4. Did the number of cormorants travel to Starling Inlet vary every day?
5. What's the energetics of such "long haul" flight? Did they really get more food in Starling Inlet than Deep Bay? Or just a gamble.
