OSLO BIRDER: Gluttony

Always a glutton for punishment, I paid another visit to Hærsetersjøen in Østfold. With wind from the NE and no fog I was hoping for more wildfowl and hopefully some raptors. Yesterday there was a very interesting movement of Rough-legged Buzzards (fjellvåk) flying north along the coast in SW Norway and I hoped that there might also be some on the move in these parts. It would be very interesting to know where yesterdays birds were going and why so many (at least 90 seen at one site) had the same idea. I assume that they were on their way to exploit a food source (there are reports of many lemmings in the mountains) but how does their jungle telegraph work?

My day though started without any raptors but still 1000’s of geese. Amazingly amongst at least 2000 Greylags (grågås) I had only the same two Bean Geese (sædgås) from a week ago plus around 50 Canada Geese – I really did expect to find at least some White-fronted Geese (tundragås) amongst them. Redwings (rødvingetrost) were obviously migrating today but I had no flocks of Wood Pigeons (ringdue) which I had also expected to be on the move.

The geese at Hærseter were unusually wary for Greylag Geese and it would be interesting to know where such large numbers come from. Unfortunately none were ringed here but not too far away at Hemnesjøen there was a single neck collared bird. The rings on these birds are in my experience very difficult to read as they have a letter and a number vertically and another letter horizontally and one really does need good views at different angles to read the ring despite the fact that the colours (white on blue ring) are advantageous. The bird I saw B2G was ringed 19 June 2012 in Vestfold, spent February 2014 in Germany and has been seen last autumn and earlier this autumn close to where I saw it. Quite a disappointing reading – I had hoped to find out it came from much further to the north although the lack of records for April- mid June could mean that it does breed further north.

the observations of Greylag Goose B2G as reported to www.geese.org

Working my way back though Akershus I had a couple of roadside Great Grey Shrikes (varsler) at new locations but still no raptors. Then I stopped to try to locate my third GG Shrike for the day (unsuccessfully) and during the course of 10 minutes had 5 Rough-legged Buzzards and a single Sparrowhawk migrating SW following exactly the same line. But as soon as they started then they finished and there were no more birds after them. What caused this little rush? I got very excited whilst it was happening and thought I might be in for a Flasterbo Lite experience but was quickly disappointed again.