After perhaps six dead herons or egrets and a dead common buzzard found in Hong Kong and shown to have H5N1 this winter, I posted this to HK Birdw Soc forum:

Indeed intriguing re just how these herons/egrets have been infected.

If not scavenging bird corpses (with Grey Heron before, I’ve wondered re scavenging dead chickens tossed into creeks),
then perhaps from water – but why so few individuals, why not ducks (which we know can readily catch n spread wild bird flus – Anatidae evidently being chief reservoirs of these wild flus)?
From fish, with sufficient virus in stomachs?? (maybe after eating poultry manure, offal from infected poultry?)