Oslo guiding and "night singer" magic

I have had a weekend of guiding. On Saturday I had the very pleasurable company of William Sutherland, Professor in Conservation Biology at my alma mater, Cambridge University. Now if only I could turn back the clock and chose an interesting useful subject to study like that instead of Economics.... Bill's email to me had been titled "Mad Idea" this being because Bill was landing at Gardemoen at 1230 and had a meeting starting downtown Oslo 1700 and he wondered if he could get some birding in between these two events. Well it wasn't a mad idea but definitely rather ambitious.
After picking Bill up just after 1300 we headed first for the Slavonian Grebe (horndykker) pair in Nittedal. Both birds were out on the lake which I took as a rather disappointing sign that breeding has failed – let’s hope not.
After this it was of course Maridalen as this offers the best chance of a variety of species. In the middle of a hot afternoon it is always going to be hard going but a fine male Common Rosefinch (rosenfink) was a tick for Bill plus we had a number of the commoner birds. One interesting bird was an acro warbler. Found the previous night and also seen earlier that morning it was reported as a Marsh Warbler (myrsanger) but the one picture showing not much more than the head had me excited. Questioning the observers I heard that the song was a bit odd which had got me even more excited. Unfortunately the bird did not make a noise for Bill and I but the glimpses we had of it in the undergrowth and in flight were of a grey toned bird which just increased my excitement - there was a good chance this was Maridalen’s first Blyth’s Reed (busksanger)!

I decided that I would make a night round in Maridalen but started at 2130 as I hoped to see the warbler in good light. Per Christian joined me and after hearing one of the two Corncrakes (åkerrikse) that PC had discovered earlier in the week at Skjerven gård we got to the warbler site (which has traditionally held breeding Marsh Warblers). Between 2130 and 2350 we heard just one brief snatch of song which sounded promising but did not see the bird and elicited no response from playback of either species. Then at 2350 the bird started to sing carefully but after about 15 minutes was in full song and here there was no doubt – Maridalen’s first Blyth’s Reed Warbler was a fact. I must admit to feeling quite chuffed that I had suspected the real ID from the one picture I saw J

Not only that but we were also listening to Maridalen’s first ever Quail (vaktel) which had been first heard earlier in the day. This was nearly all too good to be true! The four Tawny Owl (kattugle) youngsters could be heard begging for food, Woodcock (rugde) were roding and on the way out of the valley we heard both Corncrakes singing. A truly memorable night.

 

After a bit over 4 hours sleep I was up early on Sunday to guide Juan from Colombia via Switzerland for the morning. I naturally asked if Blyth’s Reed Warbler would be of interest and it was so became our first stop. The bird was singing loudly when we arrived from a clearly favoured bush but despite it being a small bush the bird was difficult to see but I did manage some pictures. After this we searched hard for the Tawny Owls but failed completely to find them. Common Rosefinches though showed well and surprisingly a Marsh Warbler sang from some lush vegetation in a damp corner of a field and showed well. It was good to be able to compare the songs of Blyth’s Reed and Marsh so close after each other. The jizz and colouration of these two birds is also noticeably if subtly different. Nearby an Icterine Warbler (gulsanger) was singing constantly  - there seems to have been a new and late arrival of this species – and it was also interesting to be able to compare this song to that of the two acro warblers as it is a potential confusion species. Leaving Maridalen we stopped at Østensjøvannet where the Slav Grebe showed well as well as Rusty the escaped Ruddy Shelduck. Yet again Oslo delivers!

Blyth's Reed Warbler (busksanger) - not easy to photograph.

here in sunlight and notice how the colour of the upperparts becomes warmer

note the long supercilium extending behind the eye again a good ID character



The relatively short primary projection is a good ID character. It is also possible to see that the wing tip is made up of a 2.3 primaries whereas the spacing between the primaries is more obvious on a Marsh Warbler

Masrsh Warbler - difficult to describe but this bird has a different jizz - it is plumper and kinder faced



here the pale feather tips are a good ID feature of spring Marsh Warblers. In this shot one can also see the P3 is the longest primary feather

Marsh Warbler - note also the long primary projection and dark centres to the tertial feathers



Blyths Reed Warbler (left( and Marsh Warbler (right)

 

no bird visible but there is a treecreepers nest behind the cracked bark