Sunday, 22 November 2020

Intermedius Lesser Black-backed Gull

A Lesser Black-backed Gull (1CY) still retaining its juvenile plumage in November! Is this a common sight? Well, not in urban north-east London, and I can't remember seeing one in this plumage on the patch before so late into the year - this chocolate brown Lesser Black-backed Gull stood out amongst the throng of Gulls on Jubilee pond (Wanstead Flats). 

As far as I'm aware all our British or 'southern' juvenile Lesser Black-backed Gulls (graellsii) have long gone through a post-juvenile moult into a 1st-winter plumage. With this being the case, seeing a 1CY bird still in this juvenile plumage would suggest a bird from the far northern colonies, mostly likely the northern tip of Norway, so you could safely presume a bird of the ssp 'Intermedius'. 

A fair number of our Common Gulls on the Flats also originate from Norway and will have followed a similar line of migration south, as the Scandinavian winter takes hold.

Lesser Black-backed Gulls (Intermedius) are not uncommon (but are far less-common than our nominate graellsii). I've seen adult birds (probably the easiest plumage to pick-out) with their noticeably darker tones in the mantle/back/wings on the Flats before, but I've never knowingly seen a juvenile, so It's been a nice little bit of Gull education. I also suspect this may have been a just a brief stopover for this bird before continuing on to southern Europe and North/West Africa and its wintering grounds, a journey of over 5000km before finally losing those juvenile feathers and moulting into 1st-winter plumage - who said Gulls are boring?

As always, comments appreciated and most welcome.

Juvenile, 1st Calendar Year
Lesser Black-backed Gull (ssp. Intermedius)

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