Q&A YOUR QUESTIONS ANSWERED

Q While watching the gulls at Grafham Water on 8 August (obviously starting with the Cape Gull!), I was confident on Lesser Black-backed and Yellow-legged Gulls being present, but the bird in the attached photo appears to have a black mark at the tip of its beak. The only bird that seems to have this is a thirdcalendar-year Baltic Gull, so is this a possible fuscus or have I let my imagination run away with me? Simon Jeffs, via email

Q

I would like to hear your opinion about this juvenile gull in Denmark. Yellow-legged or Caspian? Thanks! Henrik Knudsen,

via email A

Josh Jones, Editor of Birdwatch, replies: “What a lovely bird! The bill is deep, with a strongly pronounced gonys and almost ‘bulbous’ tip. The head is quite square-looking due to the sharp angle at the hindcrown, with a dark ‘mask’ over the eye. The legs are long and pale, but still look quite well built. The pale fringing to the coverts is narrow and crisply demarcated, with the inner greater coverts showing strong pale notching. Similarly, the dark brown tertials show only narrow and crisp pale fringing ... this is a juvenile Yellow-legged Gull.” A Josh Jones, Editor of Birdwatch, replies: “Most features on immature large gulls are incredibly variable and bill pattern is no exception – there are very few (if any) cases where a species can be identified by this alone. In line with this, the black mark on the upper mandible that you refer to is not a distinguishing feature of Baltic

Gull and is instead down to individual variation that can be seen in many large gull species – in fact, you may have noticed that the Cape Gull also showed such a dark marking on the leading edge of the upper mandible.

“As for the subspecific identification of your bird, a starting point is the tone of the upperparts. Despite the strong sunlight, we can see that this bird has dark slate-grey upperparts which fit more with the British-breeding graellsii (which is the expected subspecies in Cambridgeshire). Baltic Gull always shows very blackish upperparts, barely distinguishable in tone from the black of the primaries. The bird is also in active primary moult, which doesn’t fit with what we would expect from a second-cycle Baltic Gull at this time of year.

“Other supporting features include the strong-looking head and bill giving the impression of a large bird, as well as overall bulk to the body.”