A local birder told me that a rarity regularly reported during the 2009 holiday season, a Cetti's Warbler, could be found around the willows at the east end of the east pond in Clissold Park. I visited that spot every time I was in the park, and one time only, on Christmas morning, I found this warbler there. The picture is at a bad angle and has a distracting background, but does confirm the ID.