Abit about Wing Moult in first winter gulls

Hopefully readers will find this post useful. Understanding wing covert pattern and the advance of wing moult was a real turning point for me learning about gulls and a really important bit of information for identifying first winter Gulls especially.

Yellow Legged Gull numbers are continuing to drop here on the inner London Thames however a few 1st winters and an adult were lurking about on Sunday morning. Below are the 1cy birds showing wing, and in the case of the second bird, tertial moult.

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Wing moult, (shown above as the darker, diamond shaped, white fringed replaced feathers dotted amongst the first generation coverts in the wing) combined with other supporting features is a reliable method for separating 1st winter Yellow Legged and Caspian from Herring and Lesser Black backed Gulls. Supposedly caused by the former two species being born in a warmer climate with earlier breeding season and therefore an older bird by the time we see it here in autumn/winter.

Up until last month I had not heard of 1cy Herring or Lesser Black-backed gulls having replaced wing coverts before spring. The bird pictured below however , photographed in Regents Park London by Dante Shepherd this October, contradicts the rule and has included c40% of its wing coverts in its post juvenile moult.  These replaced feathers are less heavily marked than Yellow in Legged gull, with a pattern recalling 2nd generation Herring gull- type scapulars rather than the seemingly dark centered diamond headed coverts of YLG.

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Flight shot shows tail pattern and large window in the inner primaries, revealing the ID of this interesting bird.

N.B: It should also be said that if a bird doesn’t show any wing moult in its post juvenile plumage it could still be a Yellow-Legged or Caspian Gull, and this method should be used carefully in combination with other features.

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Today I received the ringing information for a 1cy Caspian Gull found on the foreshore at Thames Barrier Park on the 25th of September. 111 days and 970 km west of its birthplace.

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The bird was rung as a chick at Reddern Germany, near the Polish border on 06.06.16. Hatched into a 80% Caspian 20% Herring Gull colony.  A couple of heavily marked second generation scapulars as well as faintly notched first generation scaps could be an indicator of mixed ansestory at some point, however the replaced feathers are brand new, adding to the bold pattern and as far as i can see are within variation of the species. It’s worth pointing this out if the colony is known to be mixed and its impossible to say for sure. For more pics of this bird click here

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2 weeks in October on St Agnes, Isles of Scilly

Whilst the North East of the country was being showered in Siberian vagrants and rarities, the opposite end of the was slightly behind in avian terms. However a few great birds and many close encounters with species not so often seen by London patch watchers, plus very good company and pretty much constant clement weather made for a great trip.

A surprise find and a first for Scilly! was my personal highlight- this gleaming 1cy Caspian Gull dropped in front of me for a matter of seconds on the rising tide at Porth Killier/Browath, accidentally flushed by fellow house mate and Larid loather Lee Amery along with 30 or so Lesser Black backs towards Gugh, the latter species were present in notably higher numbers the day that the Caspian arrived. The bird wasnt seen again although number of Mary’s birders were high the following day.

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Due to occasional showers and an aching back, i didn’t always have my camera on me, but a few choice birds around the island were showy enough for a few shots now and then.

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Firecrests were seen and heard most days.

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Northern Wheatear

 

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A few Spotted Flycatchers were seen over the two weeks, including this 1st year bird that littered the ground under its perch with Red-Admiral wings.

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At times there were up to 6 Black-Redstarts on Periglis beach, with a couple of lone birds dotted about the island

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Tame old Scilly Blackbird

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Yellow-Browed Warblers were a daily occurence and seemed to fluctuate in numbers during the two week stay,  some days seeing 10+ on Agnes alone.

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There were two Red-Breasted Flycatchers in the Parsonage, a British tick for me! After a few near misses over the years.

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The Eastern Yellow Wag on st Mary’s (above) If accepted will be rarer still than Siberian Accentor in the UK…

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A tame Lapland Bunting was a half hour lying on my belly spent well.

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The last chance saloon!  this Red-Flanked Bluetail gave myself, Laurence Pitcher, Graham Gordon and Lee Amery (finder) a private show away from the crowds on our final day. Stoked for Lee for finding one of the last few BBRC Bluetails as it comes off the list this year apparently.

Just before the news of the Bluetail broke, the beginning of a long and widespread story began. Laurence Pitcher and I were handed a dead ‘Yellow-Browed Warbler’ by Islander Fran Hicks that had flown into his window at the lighthouse, the crazy story goes on from there and can be read in full here

A great two weeks away from the patch, although I hardly felt away from it with fellow Walthamstow enthusiast David Bradshaw being an October feature on st Agnes for many years.   Lovely people and lovely birds even the ones i missed out in this quick summary. But i’ll be spending more time year on this unique Island for years to come.

1cy Caspian Gull, Thames barrier park

 

 

A new spot along the river for me and good first visit. This German ringed 1cy Caspian Gull was hiding behind a cormorant for the first 20 mins after my arrival. Light conditions were very changeable and poor for photography at the best of times. I’ve not seen this age in September before so the developing scapular pattern is fairly unfamiliar to me, but through bins the bird had the 4 couloured appearance of; white head and underparts, grey tones appearing in the mantle, brown coverts and tertials and black primaries and bill. This stands out more in birds post October.

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The last two shots showing the pale underwing, broad un-tapering tail band and almost un-marked upper tail. Diffuse Wing bars made by the pale tips to greater and outer median coverts Also broader more patterned window than i’d expect on a Yellow Legged gull, of which there were a few individuals.

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2cy YLG

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Adult YLG

I have contacted the Ringing project leader and will post the birds ‘story’ when i receive it.

2cy Gull, Thames o2 Greenwich

 

I originally had this bird down as a Caspian gull, this ID seemed the best fit on account of its very white underwing, the solid greater covert pattern and the ‘soft focus’ appearance of the replaced wing coverts and scapulars as opposed to the heavier marked and more contrasty remaining coverts of 2cy Yellow Legged Gulls at this time of year. It obviously also shows the features that are shared by both Yellow Leg and Caspian gulls of this age.

I’ve seen it since a couple of times and have had doubts as to whether it might just be a clean looking Yellow Legged Gull with a plain white axiliaries and white underwing.

The views I had originally were mostly from a position situated below the bird, fairly brief and in dying light.  Here are the problems ; The overall Jizz (the main thing thats bugging me), The iris is paling (which you can just see in a couple of the photos below and the last time I saw it the iris was even paler, almost bright.) Also no mirror on p10 (growing), not all Caspian Gulls at this age show it but it is apparently very rare in Yellow Leg, the bill is probably within range of Cachinanns but more suited to Michaellis. All this means its going down as a Yellow Leg, possibly with Cachi influence. Comments welcome

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Thames Juvenile Yellow-Legged Gull, ringing recovery HD232

 

 

I came across this small mucky looking Yellow-Legged Gull the other day on the Thames foreshore at North Greenwich. The ring itself being yellow made me think of recent photos of rung Caspian Gulls and how this bird may have come from that part of the world rather than other young YLG ring recoveries I’ve heard of being from southern France along the Mediterranean .

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It was rung as an unfledged Pullis at Neuenburger See in Switzerland on the 11th of May.  Its so interesting to get these further afield recoveries, especially so close in date and far in distance.  Its quite an atypical looking, Small bird,resembling Lesser black backed in a few features but looking nice having moulted 85% of it scapulars and window in inner primaries etc.

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Numbers of Yellow Legs seem to have dropped a little at Greenwich in the last two visits, and I’m still to see a Caspian gull this season. The remaining birds however are looking beautiful as they approach first winter plumage.

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The below bird was only seen in flight, taken at first for a juvenile YLG, closer inspection of the image showed it to be a 2CY bird.  The iris is starting to become pale, P9 and P10 are growing, all wing coverts and tertials replaced as well as tail and adult grey feathers coming through in a few scaps.

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Below is a Juvenile YLG in a similar flight position for comparison, taken in Marseille in Early August.

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Spotted Flycatchers, Walthamstow

 

 

 

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We struggle for good autumn migrants on the patch. Wanstead seems to pull in all the Redstarts and Pied Flys.  So when David, Paul and Lol found a Spotted Flycatcher in the sheltered area along the central path, I made sure I paid it a visit the following day. Surprisingly it was still there and joined by two others. Rarely sitting out in the open the birds stayed within cover for most of the time I watched them.

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David had seen a Wheatear on the Lockwood and a few common warblers, as well as five or so Swift feeding over Banbury.  A group of mostly juvenile Gulls on the causeway between number four and five reservoirs held a nice Yellow-Legged and Great Black-backed, both juveniles. The Yellow Leg stayed out of camera range and is the third juvenile I’ve seen this year.

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Juvenile Great-Black back

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Goldcrests seem to have bred on in or near the pub carpark this bird and several juveniles were in a tit flock nearby the other day.