7th April

A less than compelling day: batteringly strong winds overnight saw passerine migration remain on hold and did far less for the sea than might have been hoped. What numbers and variety there were were all on the sea, with 24 Sandwich Terns, 2 Great Skuas and an Arctic Skua from the Bill, 6 Red-throated Divers, an Arctic Skua and a Little Gull from Chesil and 61 Sandwich Terns, 5 Common Terns, 2 Great Northern Divers and a Little Gull through over Ferrybridge. A pitiful selection from the land included nothing of significance beyond a Merlin at the Bill.

This is a photo that slightly disproves something we'd always taken as read, which is that moulting Great Northern Divers are temporarily rendered flightless by simultaneously shedding all their flight feathers (that is the case - we've just looked it up to check!). Many years ago - when we birded Weymouth - we got quite into watching at this time of year an annual moult gathering of Great Northern Divers in Weymouth Bay; several times we saw birds flap their wings and reveal just 'stumps' without any flight feathers. Today's bird is clearly making a fair bit of moult progress, with its bill already colouring up and new plumage visible on the head, shoulders and wing bases but it's also patently completely fully-winged. Thus far, we've only been able to find one relevant notebook from the old days but this does record on 20th April of that year an individual off Lodmoor in 'mostly' summer plumage but with no flight feathers visible when it flapped, so we're guessing the flight feather shedding usually occurs after head and body moult has progressed a bit further than it has on today's individual, rather than as soon as moult begins? © Pete Saunders: