Sunday 20 March 2016

A Review of the Gulls at Shawell During 2015

2015 was another good year at Shawell, with the landfill site continuing to attract many thousands of gulls to the area. 

Most birders stop looking for gulls during the summer months, but summer can actually be one of the most productive times. A first-summer Baltic Gull at Cotesbach landfill site in early July (subject to acceptance) was the highlight for me. Once again the eagerly awaited influx of juvenile Yellow-legged Gulls occurred in July. 

My sightings of Mediterranean Gulls increased during 2015, but sadly I failed to read colour-rings fitted to two of them

Caspian Gulls continued to entertain and frustrate me in equal measures throughout the year. The mixed colonies of 'Large White Headed Gulls' in Germany produce some hybrids that can be challenging when they turn up at Shawell. The regular Polish ringed Caspian Gull PADZ was back in Leicestershire again this year favouring Shawell in January and again in August. PADZ moves between  Shawell and Albert Village in the north-west of the county.

Species Accounts:

Black-headed Gull    Chroiccocephalus ridibundus

Present throughout the year with numbers peaking as usual in late-winter.

16 colour-ringed birds were recorded. Several from Poland and one from both Latvia and Lithuania.

Mediterranean Gull    Larus melanocephalus

A good year with my best annual total so far. 
  • Adult, near summer plumage, February 17th (un-ringed)
  • Adult, summer-plumage, February 25th (Polish colour-ring)
  • Adult, near summer-plumage, March 14th (un-ringed)
  • Second-winter, March 14th (un-ringed)
  • Adult, full summer-plumage, March 18th (Polish colour-ring, different to one on February 25th)
  • Two adults, summer plumage, July 4th (one had a metal BTO type ring)
  • Juvenile, July 11th (un-ringed)

Common Gull    Larus canus

As normal this species is present throughout the year, but in small numbers. 

Just two colour-ringed birds were recorded, one ringed by the North Thames Gull Group and the regular Norwegian bird (JEJ8), which was first seen at Shawell in February 2011.

Lesser Black-backed Gull    Larus fuscus

This is the most numerous gull species throughout much of the year apart from mid-winter when numbers drop as low as 300. However, during migration times and even in mid-summer counts of around 2000 are not unusual.

The majority of colour-ringed gulls are of this species. In 2015 I read 184 new colour-rings plus many re-reads of colour-rings I'd seen in previous years. A second-calendar year bird, ringed in Denmark, was at Cotesbach landfill on July 25th and the next day I saw it on top of the roof of Casepak recycle centre in Leicester.

Baltic Gull Larus fuscus fuscus 

  • July 11th, first-summer Cotesbach Landfill.
During a session at the landfill site I spotted a really distinctive gull. Realising that it had nice fresh looking 'tar black' primaries quickly focused my attention. First-summer Baltic Gulls time their moult differently to first-summer Lesser Black-backed Gulls. During the summer second calendar-year LBBGs have worn and faded primaries with maybe a few either missing or re-growing. Basically first-summer LBBGs look scruffy. This bird has fresh looking primaries, new third generation tertials, many new scapulars and median coverts. It is also moulting some of its greater coverts and its underparts are clean white. Add this to its general structure and I think it is a good candidate. Many others agreed and so I have submitted it to the BBRC. First-summer Baltic Gull are identifiable based on moult timing according to a recent study.

First-Summer Baltic Gull (subject to acceptance by the BBRC)
  • August 29th, Adult at both Cotesbach Landfill and Shawell A5 Lagoons
I first spotted a very black looking Larus fuscus at the landfill site, but one of the machine drivers drove in front of it and started working. This disturbed the gulls and they flew to a distant part of the quarry. Luckily I picked it up during the afternoon at the A5 Lagoons and enjoyed prolonged views. Its plumage was spot on for the nominate form of Lesser Black-backed Gull (Larus fuscus fuscus), or Baltic Gull. It small elegant body and long wings are good for this sub-species as well. Without a colour-ring it is best to say it is a gull showing characters of Baltic Gull.

Presumed Baltic Gull

Herring Gull    Larus argentatus

Seen in all months with numbers peaking in late December. The highest count was c3000.

I recorded 33 colour-ringed birds including two from Norway, one from Russia and the Finnish ringed adult first seen in 2014 reappeared in November this year.

Yellow-legged Gull    Larus michahellis

Seen in all month’s with the highest numbers being present during mid-summer, as usual. The highest count was 33 in the same group at the landfill site on July 29th. One of the highlights is seeing the influx of juvenile Yellow-legged Gulls during July. The first juvenile gulls to be seen are almost always of this species. 

Juvenile Yellow-legged Gull, Shawell A5 Lagoons, July 2015

Caspian Gull    Larus cachinnans

Another good year for this species. In total I saw 43 different birds

January seems to be the best month, however, sightings can be expected throughout the year. April and May were the only months I drew a blank. The challenge to find a juvenile in August proved difficult with the best contender possibly being a hybrid.

Understanding the variables is the challenge with many gull species and probably none more so than this one. It is all too easy to label any possible Caspian Gull with a few non-typical features as a hybrid, but care has to be taken not to jump too quickly to this conclusion. As with other gull species there is a great deal of variation between individuals, especially immature birds. Probably the best method to rule out the possibility of hybridisation is to use the 'trait scoring system'. This really requires photographs, but didgiscoped images are usually OK. For anyone interested in learning more CLICK HERE.

The colour-ringed Polish adult (yellow PADZ) that I first saw in 2014 was back during January and August. In addition a new colour-ringed Polish first-winter (red 10P6) was seen on two occasions during November.

Iceland Gull     Larus glaucoides

Just one recorded.
  • Juvenile on March 14th at the A5 Lagoons

Glaucous Gull     Larus hyperboles

Two were recorded in January. 
  • Second-winter on January 20th and 24th at both the A5 lagoons and the landfill site.

  • Third-winter on January 25th at the landfill site.

Great Black-backed Gull    Larus marinus

Seen throughout the year apart from May. Numbers are at there highest during January and December. The highest count was 650 in mid-January.

Six colour-ringed birds were recorded, all but one were ringed in Norway and the other was from Denmark.

Other Reviews:

1 comment:

  1. What a great list of Gulls mate,keep up the good work.....