I thought I’d put a few comparison shots up from Princes Park. I went down again today, the weather being not much use for anything else. Beachy Head is shrouded in low cloud whilst being battered by a gale force wind. Weather better suited for late October!
I look at gulls a lot, but still I’m frequently baffled & fooled by the variety that occurs within a single species. Variation amongst the larger gulls, both in plumage and size often leads to me seeking a second opinion on a tricky bird. Below a few “side by side” shots of juvenile Herring and Yellow-legged Gulls. It would have been nice to include Lesser black-backed Gull but they’re not a common species here. The comments made below are only relevant to juvenile birds.
Yellow legged Gull
The above shots demonstrate nicely how plain winged YLG’s should appear. Herring Gulls have broad fringed and deeply notched wing coverts and tertials. The YLG’s tertials are essentially plain with minimal fringing limited to the tip. Not extending along the length of the whole tertial feathers. On average YLG’s tend to be whiter on the body, (although this is quite a pale Herring Gull!) often looking white bellied in flight when viewed from below. The classic, longer legged look of YLG is nicely shown off. This YLG is quite demure, probably a female. See the post here for a bigger, male type YLG from July.
Yellow legged Gull.
YLG’s in flight should have a striking quality. Compared with the Herring above, it gives you a good idea how different they should appear, when presented with a classic individual. Key features are the tail pattern and the lack of an extensive pale window in the inner primaries. I also find the synchronicity of tone between the tail band, secondaries and outer primaries a good visual key when dealing with a bird in flight. The above bird also demonstrates how solid the spread wing looks when compared the heavily notched feathers on the Herring. Reminiscent of juvenile Lesser black-backed Gull but they would show an even more concolorous, wholly dark upper wing with virtually no pale in the inner primaries.
Yellow legged Gull
Two juveniles on the water, similar comments would apply here to the two standing birds. A nice demonstration of how contrasty YLG’s are over Herring Gulls. We should start to see the first new mantle feathers coming through on the YLG’s any day now, being ahead of the Herring Gulls by 3/4 weeks. You can see that older age (being born earlier in the year further south in Europe) in the worn feather edges on the YLG, compared to the brand new feather edging of the younger Herring Gull.