BIRD GUIDING AROUND OSLO

Friday, 16 September 2011

Fornebu again...

A probable female Black-eared Wheatear was seen at Fornebu yesterday evening so that was a good enough reason for me to get down there today. Unfortunately all the Wheatears I saw were bog standard Northern/Common but a pleasant time was had. Blue skies and almost no wind were not the best weather for finding something interesting and a female Redstart was the highlight on the passerine front. It took a while before I saw the tail on this bird as it skulked low down in a bush and I was thinking far rarer alternatives for a while. Alongside the Redstart was a Crested Tit in completely atypical habitat - sallow bushes in the middle of wasteland.
The nice weather did at least encourage the local raptors to show off with singles of Kestrel, Merlin, Sparrowhawk and Goshawk. The Kestrel was particularly showy and was mobbed by both the Merlin and Sparrowhawk in addition to local Crows and Jackdaws.
Lingering summer visitors were Yellow Wagtail, Chiffchaff, Blackcap and Swallow plus Dunnock.
I decided to pay attention to the Cormorants today as both subspecies (Carbo and Sinensis) have been reported and sure enough I found both to be present. The following photo has a Carbo (the northern cliff nesting subspecies) on the left and 2 Sinensis (the southern tree nesting subspecies) on the right.

How do you tell them apart? Well the differences are rather subtle. If you click on the picture you will see a large higher resolution version which will help. On the bird on the left notice how the angle of the gape (the innermost area of the yellow around the bill) is rather actute whereas on the righthand bird it is squared off. Additionally notice that the right hand bird has far more yellow around the bill (this is called the gular area) and less white surrounding the yellow than the left hand bird.
Definitely subtle differences but there are enough behaviourally differences for them to be classified as subspecies although here they seem to be quite happy hanging out together.

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