BIRD GUIDING AROUND OSLO

Thursday, 2 August 2012

Large Gulls


It was raining cats and dogs today but I had a chance for an hour of birding so took it. I hoped that the rain would have brought down some waders but at my first port of call, Maridalsvannet, the water levels were far too high for any waders. A nice surprise was a well grown young Black-throated Diver (storlom) with an adult (the other adult was feeding nearby). The often fluctuating water levels here usually make it difficult for the divers but the wet spring and summer has meant little fluctuation which has been good news for the divers although has meant few waders for me.
At Rolfstangen, Fornebu there were 15 Knot today, an increase of one from two days ago. Also an out of place and probably sick Fulmar sitting on the water. Some good views of the local gulls. A juvenile Lesser Black-blacked Gull (sildemåke) had sat close to an adult Great Black-backed Gull (svartbak) which caused consternation to one of its parents which dive bombed the GBBG for a number of minutes before the youngster decided to fly off to another island.
The young LBBG came far too close to the GBBG for its parent's liking

The local breeders are of the subspecies intermedius and here is a picture of one of the adults. You see that although it is dark on the back that it is still paler than the presumed fuscus I saw in Nordland. It also has a white mirror on P9 and white tips to the outer primaries which were missing on the fuscus.
Adult Lesser Black-backed Gull ssp intermedius


Also a juvenile Herring Gull (gråmåke) and LBBG sat side by side allowing an educational picture to be taken where the subtle differences between these birds can be seen.
Juvenile Herring Gull (left) and juvenile Lesser Black-backed Gull (right)

The Herring Gull on the left is slightly larger and pale but the most important difference is on the tertials which in the LBBG are dark with a pale edge whereas in the Herring Gull are a creamy brown with the pale edges jaggedly intruding into the darker centres.

Driving home I had my first Nutcracker of the autumn flying over the road. Soon they will appear in the garden to eat hazel nuts.

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