Selsey Bill, Black-throated Diver

After a week of cold easterlies, frosts and snow, today was brighter but still with a cold northwesterly. The highlight of a couple of hours at the daily seawatch was a Black-throated Diver and also a single Great Northern, 6 Red-throats, about 50 Kittiwakes (they've been moving across land this week, see here for a cracking group at Port Meadow, Oxon HERE) and Common Scoters, Red-breasted Mergansers and Razorbills. Ebird list HERE . More photos and other news from the Peninsula as usual on the local blog HERE

Black-throated Diver was a Peninsula/Sussex tick, now on 176 HERE. 

There is an incredible transformation of the weather predicted for tonight. We should be going from frost and freezing wind today to saharan sand in the morning and day time temperatures of 17 C by Sunday. It's nearly freezing (about 3 C) outside at the moment but I've put the moth trap on because around mid-night the warm air comes in (possibly with moth migrants at the leading edge) and by the morning it should be 10 C.  A lot of wind and rain comes in too so will be interesting what happens. 

Black-throated Diver (above and below).  A few diagnostic features include the evenly curved bill (lower mandible strongly curved in Red-throat), over 50 percent of the neck is dark (much less in Red-throat although juveniles have a diffuse wash) darker along the bottom edge , with a broadish flank line (diffuse and broken on Red-throat) and unmarked white auxillaries (marked with long streaks on Red-throat), the white flanks wrap further up the rump and the trailing legs are large and well protruding. NB. The flank stripe is a diagnostic feature for in-flight Pacific Diver which has a broad and even stripe. (HEB, Duivendijk 2024) 

Red-throated Diver for comparison showing the curved lower mandible, only half of neck is dark, there are streaks/marks on the auxillaries, the flank line looks solid and broad in this bird, actually more substantial than the Black-throat (generally more diffuse and broken, so usually the opposite), there is no wrap up of the white underparts towards the rump and the trailing legs appear a bit less substantial

Red-throated Diver (left) and Black-throated Diver (right), side by side comparison shots (above and below). In the pic below the slightly larger size and heavier structure of Black-throat is exaggerated by the photo effect. 

Great Northern Diver - even at this distance the overall jizz, bulk and long thick trailing legs of the bird suggests a Great Northern. Not sure what the gull is, in clear winter skies looking into the sun it wasn't easy viewing this morning.  

Little Oak Lodge in yesterday's wintery conditions