There are images of a possible European Herring Gull in Florida
European Herring Gull , Volusia Co., Florida, Tomoka Landfill (Volusia Co. Landfill) January 27, 2008 © Alvaro Jaramillo
Poss. Euro Herring Gull. Showed pale rump, extensive white barring on base of tail, wide bars on outer greater coverts, striking pale inner primary window etc. It also was more greyish than smithsonianus, and showed blacker tail and primaries, both with thin white tips.
European Herring Gull, Volusia County Landfill, Florida January 27th 2008 © andy wraithmell- 2nd state record
Obviously, this sticks out from classic American Herring Gulls, and appears to have lots of good European Herring features (tail band, pattern of coverts), but I have looked very carefully at this and wonder, is it just me or is there something strange about the pattern of the rearmost scapulars, that is not quite right for first-winter argentatus/argenteus? In addition, the pattern of the new 1-w scaps seems slightly strange also. I went out and checked the local argentatus/argenteus mix we get here in Suffolk, and came away still feeling just a little uneasy. Maybe it is just me taking a very cautious approach - it is a heck of a long way south for European Herring (level with just north of the Canary Islands) - and I don't want to sound too negative.
I further wondered, as within the argentatus/argenteus group, where some birds can appear to possess a large number of pro simthsonianus features, is it possible that odd, pale smithsonianus ever look like this? I feel sure that Alvaro with experience would not be suggesting this if he thought they could....