After Justin left Selsey Bill this morning, the watch continued and several hundred Commic Terns continued to pass. However, best news was of 2 single Pomarine Skuas which gave good views; one settled on the sea for over half an hour before departing. A short interlude at Northcommon Farm/N Selsey produced 3 Spotted Flycatchers, a Garden Warbler and a family party of 4 Mistle Thrushes. Back to the sea where passage continued...then the day's mystery bird. An all dark petrel-like bird headed E about 3/4 mile out and was watched by 6 observers for 10 mins. First thought was a possible small falcon, but no, flight was wrong, flap flap flap flap short glide low over the waves, it was surely an all-blackish sea-bird, eventually lost to view well out. Dark-rumped petrel??? A quick phone call to Portland came up with a suggestion...female Nightjar, similar to those seen there previously. Well it's quite possible! In truth we will never be sure, but it was interesting and was the subject of much debate. Anyway, it was great to see some real passage at last...now that's better!