Thursday, 29 January 2015

The wrong type of gull

Oslo on foot yet again failed to give me any real results and definitely no rare gulls although I am sure that my body will thank me for it (in the long run).

A real surprise was singing Wood Pigeons (ringdue) at two sites. In a normal winter this species doesn’t occur in Oslo in January but this year there have been many records but for them to be singing and engaging in their display flights is quite extreme. Another extreme record was a Grey Wagtail (vintererle) in Frognerparken. There have been a couple of other records of this species in Oslo this winter and it could well be that there is a bird overwintering. Also in Frognerparken were 6 Teal; 5 were quite shy birds and the 6th a ringed female that has spent the last few winters eating bread with the Mallards.

The Caspian Gull didn’t turn up during the hour I gave it and things became so desperate that I started looking at the Herring Gulls in more detail than is healthy. I read four colouring rings but as nearly always seems to be the case there was little interesting data from them despite them all have been recorded multiple times: all had only been seen in the Oslo area away from breeding sites.

whilst whiling away the time I took a number of pictures of Herring Gulls in differing plumages but only realised once I uploaded them to the PC that I had completely the wrong setting on the camera so they are of poor quality.
Adult Herring Gulls (5cy+)
this bird (J4424) was ringed Jan 2013 and was already aged as at least in its 5th cy making it a 7cy+ now. It has been reported in Oslo the last 2 winters but there are no other reports. This bird is particularly streaked on the head with a dull bill perhaps suggesting it is a northern breeder

a very clean adult with a much brighter bill - perhaps a local breeder 

I find no brown feathering in the tail or wings meaning this bird is at least a 4th winter (5cy). The dark band on the pale bill suggest that it is this age though and no older
4th winter (5cy)
Due to this bird being ringed (J2298) in October 2011 we know it is in its 4th winter (5cy) but without the ring it would be difficult to differentiate this individual from an older bird although the bill is a sign of immaturity
3rd winter (4cy)

this bird can be aged as a 3rdwinter due to the brown in the tertials and coverts plus a faint tail bar

a different bird but showing the same combination of a quite adult like general appearance but with some brown in the wing and the tail. This bird also still has a dark eye

2nd winter (3cy)

This age group is very variable with some birds looking at first glance like 1st winters whilst others are so advanced they look like 3rd winters.
this age class is very variable. This bird has some grey feathers on the mantle

this bird has hardly any grey feathers on the mantle and is not straightforward to age but note it has a pale eye and two toned bill which say 2nd winter plus the pattern of the greater coverts is also 2nd winter. The primary feathers do look very pointed though which is normally a sign of a bird in its 1st winter

a farly advanced 2nd winter with nearly completely grey mantle 

another bird with little grey and also still a dark eye
an advanced 2nd winter with nice white tips to the primaries unlike the other birds
1st winter (2cy)
a rather dark bird but note the lack of grey feathers in the wing and mantle compared to 2nd winters. Note also the different pattern of the covert feathers.

a paler bird but the pattern of the coverts is still 1st winter

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