First major die-off in wild/ornamental birds with H5N1 of Guangdong goose 96 lineage was in 2002, in Hong Kong.
Were more deaths in 2003/04.
But, didn’t cause so much fuss as those now – and Qinghai Lake incident remarkable.
So, seems H5N1 has always been deadly to wild birds. Some variations in ducks (rather more guff in another thread or two here:Trojan ducks, PNAS paper).