Earlier in the week I noticed a juvenile gull laying down by one of the pools at the Cotesbach landfill site. It was juvenile Yellow-legged Gull like, but something nagged at me. I didn't see it standing up because the gulls were spooked and they flew off very fast. This morning I picked out what is almost certainly the same bird stood in one of the shallow pools. The light was poor, so I videoed it knowing that I could get some screen grabs. I identified it as a juvenile Caspian Gull at the time and I am still of the same opinion after studying the images of it and comparing it with photographs of known juveniles Caspian Gulls.
Juvenile Caspian Gull
Juvenile Yellow-legged Gull for Comparison (note the notched greater covert pattern)
It is longer winged and longer legged than the juvenile YLG's I've seen recently; its body is more elongated and slender; its head is smaller and slightly darker compared to juvenile YLG; its bill is not as massive and lacks the really obvious gonys angle of the juvenile YLG's pictured in recent postings; its greater coverts are brown centred with fine pale edges, which is good for this species and its tertials are not so finely edged white as in most juvenile YLG & LBBG.
Many juvenile Lesser Black-backed Gulls were present and most of them were much darker headed although a few frosty looking northern birds were present today. The leg length and the much longer body and wings easily seperated it from the juvenile LBB Gulls. A few juvenile Herring Gulls were present too and they were obviously different: larger headed, shorter legged and more greyer in tone.
Juvenile Caspian Gulls are quite rare in England, however, this almost certainly has more to do with the difficulty in identifying them and the poor coverage of this age in field guides. The features are subtle, but can be seen if looked for.
Juvenile caspian Gull
The long spindly legs help to rule out Yellow-legged Gull. The long length of the exposed tibia is very obvious in the pictures.
Juvenile Caspian Gull
The video below shows it in comparison to a juvenile Lesser Black-backed Gull. Sadly the quality of the video is poor, as it was filmed through waving grass stems just before it started raining. Check out its long legs and the amount of tibia exposed plus its body shape and the angle its body is to its legs for most of the time. Hint: It's the middle gull...
