In 28 years of birding, often full time, I've many of great moments. However, if I stuck to Europe for now, I have an incredible two days in SW France in 2012 that I can't forget.
I was on a 10 weeks mission couting the migrants at Cap Ferret (2012) for LPO (French equivalent of RSPB). Early November, while I thought birds would decrease, a huge migration started again after a week of rain.
Sky was full of siskins, chaffinches, bramblings, thrushes, and so on.
I heard a call of a "strange wren", wondered what it was. The bird was hidden in a very low vegetation on the sand dune, behaving like a Dusky Warbler. And there it was, short but good views.
A few minutes later, I see a small bunting flying towards me. It stopped in a small bush. Excellent views of a Little Bunting...
Later on, I saw two birds fighting in the air, then suddenly dropping down to a small tree. If the Great Tit was obvious, the other one was unknown. When it perched in view, the wide eye brow made me think a half second of a late Whinchat with a long tail... no, of course. A beautiful male Rustic Bunting!
Sharing this online made several birders to join me the following day. It was still good, with noticeably a gorgeous White-tailed Sea Eagle flying low in the morning mist above the beach, a spectacular male Snow Bunting in a Chaffinch flock, or another Lapland Bunting (rare that far south) turning around us like to stop, but finally cross the Basin d'Arcachon to the Pyla Dune.
If I have to select ONE of those birds, Rustic Bunting on the top of the small tree, even if it didn't stay and I missed my photo, was the top of the top.
Cheers