BIRD GUIDING AROUND OSLO

Tuesday, 22 September 2015

Hybrid blues

Feeling some post-Værøy blues I visited Årnestangen today and saw hundreds if not thousands of birds which was a bit of a contrast to Værøy’s meagre pickings. There were many, many thrushes, mostly Fieldfares feeding on rowan berries but also Yellow Wagtail and Chiffchaff. The water level is high with no mud banks left and some of the fields flooded and the wildfowl are concentrated on Fautøya. Here among hundreds of Mallard, Wigeon and Teal were three Shoveler and two Pintail. Amongst a small flock of Canada Geese was a single Greylag Goose and 5 juvenile hybrids between the two species.

I had my first migrating flock of Pink-footed Geese for the autumn with a flock of 200 heading south of which a group of 20 broke off and flew around the area seemingly looking for somewhere to feed. When I first heard the flock I thought they were Bean Geese and realised that I cannot separate them on call. I also find it to be far from straightforward to separate these two species in flight if one doesn't see the overwing and it is clear from the number of records of migrating Bean Geese from certain areas of the country that others have similar difficulties. Bean Goose is a truly scarce species in Norway which we now know to have very traditional migration routes yet the number of records from some areas would have you believe it to be much more regular…..

I had pretty good views of 2 Hen Harriers both of which were 1cy birds but taking good photos of them remains a challenge for me. Driving up to the main road a spotted what looked like a Carrion Crow but suspected it would turn out to be the hybrid that has been reported a few times here recently. At some range in the bins it looked very black and pure and it was only by studying the photos I managed to take that evidence that it is a hybrid were evident. Compared to the two hybrids I have seen before this bird was much, much blacker and is I suspect a second or third generation hybrid with just a single Hooded Crow ancestor. It may also be a pure Carrion Crow that has a few dark grey feathers although a quick google search failed to find any pictures of similar birds. It also raises the question (as the Black Duck hybrid and various gulls do) as to where one draws the line between a hybrid and what can be called a pure bird.
five Canada x Greylag Goose hybrids

Carrion Crow x Hooded Crow hybrid but a bird at the Carrion Crow end of the hybrid spectrum

no grey to see in this photo though

this picture isa bit to grainy to make much of but there appear to be a few grey feathers amongst the black. Then again though it looks like there is grey on the upper breast where both species are black so maybe the grey feathers are not because of a hybrid influence?

1cy Hen Harrier - looks to have a dark eye and is therefore a female

same bird


2 juvenile/1st winter Lesser Black-backed Gulls showing a bit of the variation in this species

here when the pale grey upperwing I visible then Pink-footed Geese are easy but depending on light conditions and the height the geese are flying then geese can be difficult
 

No comments:

Post a Comment