A nice crest and a difficult Chiffchaff

Yesterday, I went to look for a singing Firecrest reported the previous day to the west of Oslo. This was the first interesting possible breeding passerine (apart from the night singers) reported this year which is a buck in the trend of previous years which had suggested that Red-breasted Flycatchers, Firecrests and perhaps Greenish Warblers were on the verge of establishing themselves as breeding species in south eastern Norway.

It was a 3km walk with the Beast but luckily we were in the shade because it was hot again. On the way out a number of interesting looking butterflies flew in the sunny areas but I did not stop as I thought we would use a leisurely walk back to look at them. As it happened it clouded over and the walk back was butterflyless despite it still being very hot.

The Firecrest was singing on arrival and hardly stopped but was not easy to see for that. It did not have a particularly orange crest and was I assume a 2cy bird.

Firecrest (rødtoppfuglekoge)

The real excitement came on the way back. I heard a distant song I could not place and eventually picked out a phyllosc singing its heart out at the top of a distant spruce tree. I was not going to be able to get any closer physically and the closest I could get to the song (in my mind) was Chiffchaff. I decided to play the song of Chiffchaff. The singing stopped but soon I was aware of a Chiffchaff in the trees close to me. It was silent at first but then suddenly burst into the same song I had previousy heard. I was stumped. There were definitely elements of Chiffchaff but other elements that were wrong. There was no mobile coverage in the area but I have quite a few bird songs saved on my phone. It definitely resembled the recording of Iberian I had but was missing the Willow Warbler like element of the song. It kept singing for a long time and I tested its response to both Common and Iberian Chiffchaff song. It responded to both but was a stronger reaction to Iberian. After over half an hour of this interesting song it (or I assume it was the same bird) suddenly sang normal, pure, Common Chiffchaff song. This convinced me that I was just dealing with a strange Common Chiffchaff (or possibly a “mixed singer”) and I left it. Getting home though and trawling the net I can find recordings of Iberian that match what I heard and Iberian is supposed to sing pure Common Chiffchaff as part its conflict song. I can also not be sure it was the same bird that sang pure Common Chiffchaff as I did not stay around long enough. I also did not pay enough attention to the contact call although have recorded what I think is it. Plumage wise I am not sure but it does have a very pale lower mandible and a long supercilium but is not very green plumaged. Without dna I think this will go down as a mixed singer or a strange Chiffchaff but I welcome any input.

Here are a number of videos where the song can be heard:

An interesting start (just after I had played Iberian Chiffchaff):





what I believe is the contact calls can be heardly weakly twice at the very begining:



this was taken at 11:53



and this at 11:57 when pure Common Chiffchaff song comes from same area (but is it same bird?)

was very distant when first sighted as it sang its heart out from the top of a spruce

when it came closer it was close but always above me or obscured or back lit. The pale lower mandible is a supposedly good Iberian character

long supercilium on right side

but shorter on left

not many green tones in plumage

this shows wing structure. The plumage looks to have a lot more yellow in it here but this is a very overexposed shot