It's April and this has got to be the best month to be trampling the sacred grounds of The Scrubs, my beleagured local patch. My early spring wanderings here are due to change, almost certainly for the worst, once work commences on the HS2 and London Underground stations that are to be built immediately north of my patch. No doubt some of that building work will spill over onto the site. I imagine that I may have just one, perhaps two springs left before it's all change.
Anyway, the past few weeks have brought in two Wheatears, up to eight Blackcaps holding territory and around five singing Chiffchaffs. Many of the resident birds are in full song including Song Thrushes, Dunnock, Wrens and Robins. I even watched the latter species courtship feeding recently. Three days ago I recorded a flyby male Ring Ouzel that showed itself for the briefest of moments before heading high to the north.
Today, we had our first Swallows that swept low over the football pitches as they headed west into the grey, rain laden horizon. I also came across the below black-backed gull. At first I thought that I was looking at an adult Baltic Gull given its small size compared to the attendant Herring Gulls.
Baltic Gulls(Larus fuscus fuscus) are seen by most authorities as a northern subspecies of the more familiar Lesser Black-back (L.l graellsii) whilst others see them as a completely seperate species. The main differences are that fuscus has a black mantle that matches its black wingtips while graellsii has a mantle that is midway in hue between a Herring Gull and a Great Black back (which itself is as black-backed as fuscus). Thus, graellsii has a much darker slate grey back than a Herring Gull and the wingtips are discernably darker as they are black. The other notable difference is that fuscus has a slimmer more elegant carriage than graellsii, a feature made more prominent by the former's longer wings whose tips extend beyond the end of the tail - more so than graellsii.
Just wait until you try to start deciphering the mottled brown immature birds. Anyway, back to the bird that I spied on the football pitches. I was seriously thinking Baltic Gull until I noticed that my bird had pink legs and quite prominent white spots on its primaries. The bird was indeed a Great Black-back albeit a smallish one - perhaps a female. Great Black-backs have pink legs as opposed to the Lesser Black-back's yellow pins. Also, Great Black-backs normally have more white spotting (or mirrors) on their wingtips than their smaller congenor.
Great Black-back amongst 2nd summer Herring Gulls
Note the slightly bigger sizeIt's always worth looking at every bird you come across, even if it is in the middle of the concrete jungle. I went home after seeing the Great Black-back to pore over a couple of books to remind myself of its characteristics. Always be open to learning more about the birds that you often take for granted.