Leucistic Coot and Common Chiffchaff

It really is awful weather at the moment and after having had a good arrival of ducks on Maridalsvannet I thought a trip to Østensjøvannet may pay off and the bird hide there would also offer protection from the elements. It was very birdy with lots of commoner waterfowl and 54 Wigeon was a high count but I had dared to hope for more. See my eBird checklist here.

A leucistic Coot turned up last year and I had seen it again earlier this year but it was a real surprise to see it today and see that it had turned almost completely white – I had not appreciated that the degree of leucism was something that changed over time.

In other news the dna results of the interesting Chiffchaff that I discovered in the spring have come back and show that it was not an Iberian as I had hoped but a Common Chiffchaff. What is interesting though is that it was of the nominate subspecies collybita rather than abietinus which is the subspecies that is considered to breed in Scandinavia. I don’t know the research behind this traditional view but the Chiffchaffs that move through the Oslo area in late autumn and which are textbook abietinus have always been noticeably different than the local breeding birds (especially on call). Whether all local breeders are collybita or this bird was a vagrant will only be discovered if more dna work is done. Both mitochondrial and nuclear markers were tested and both showed the bird to collybita so ruled out a hybrid as well – the classic dna test is only of the mitochondrial which only reveals who the mother is so never actually rules out the hybrid option.

The leustic Coot (sothøne) with a normal bird

despite the rain this Sparrowhawk (spurvehauk) was still out hunting

this male Kestrel (tårnfalk) was more of a surprise and looked to be heading purposefully south

Little Grebes (dvergdykker) have become a regular autumn feature at Østensjøvannet

there were still three juvenile Lesser Black-backed Gulls (sildemåk) hanging around although the adults are already long gone

this bird doesn't seem to have moulted any feathers whereas the previous bird had some newer mantle feathers

for comparison a young Herring Gull which has also moulted some mantle feathers. This is also a pale bird with milky coffee coloured primaries

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