After heaving a huge sigh of relief that the petrel was still on show as I 'scoped it up at 16.20 on Thursday, soon after my arrival, I spent the next 2 hours 20 mins watching it intermittently until its departure high to the east at 18.40.
(I checked its exit direction with my compass yesterday morning; - from where a group of us were standing on the "Rucks" its heading was 120 degrees, but from its start point in the middle of the Flash, it did leave in fact leave pretty well due east).

The best views were to be had from the Rucks at around 18.00, though the only other person around there to share it with then was a fisherman, who had enquired what was happening and who became really enthusiastic after sharing my 'scope with me.

After enjoying prolonged views of all its obvious characters in flight, (and noting no sign of any wing moult) and enjoying the ease with which it evaded its occasional pursuers, later it settled on the water some 80 yards distant. With good sunlight behind me, I was able to study finer points like the droop of its bill and its dark liquid black eye. What did strike me particularly was the unexpected solid dark grey of its head and mantle plumage, in contrast to the black of its folded wings.

Reading up this morning (Albatrosses, Petrels and Shearwaters of the world, - Onley and Schofield) under "Moult and Wear" its says:"Fresh sooty grey feathers of mantle and coverts become browner with wear. Primary moult begins after adults leave colonies, usually in August and continues at least until April."

My experience of Leach's Petrel in UK was previously restricted to Oct gales at New Brighton in the 70's and 80's, so to be able to study an individual for so long at Pennington was a real bonus for me; this is also a bird which I have never seen off the Durham coast, where Storm petrels are the commoner species (normally passing earlier, - from the third week of July onwards).
Despite my lack of experience though, I venture to suggest that the Pennington bird was a 1st Cal. year.

Nice to meet so many Manky birders!

Regards,
Mike P.