#3985
imported_Martin
Participant

Message I’ve sent to group re h5n1 and conservation:

Swan infections indeed extraordinary.
Are these all mute swans, from Caspian Sea westward?

Though had whooper swan die in Mongolia last summer, no other wild swan deaths that I’ve noticed in east Asia.
Bewick’s swans winter at Poyang, say, in some numbers (sorry, don’t have figures; quick google reveals a bird tour counting over a thousand).
Were some bird deaths at Poyang around time Guan Yi et al obtained samples including from six ducks with H5N1 – but if lots of swan deaths, it has been kept quiet. If few or no swans died there, when sharing shallow lagoons [as reserve appeared to me my one visit – the huge lake shrinks in winter, only part is reserve] with infected ducks, surely more puzzling.
As I recall, black and black-necked swans have died of H5N1, in captivity in Hong Kong and neighbouring Shenzhen.

Qinghai indicates geese (well, bar-headed, tho again have been deaths in captivity) highly susceptible. Also graze in fields [as swans may do]

info from ornithologist Chris Feare:

Quote:
Swans do indeed seem to be highly vulnerable and I cannot say why. They do
graze arable crops and grass, and they can forage on the bottom of water
bodies deeper than accessed by dabbling ducks. There may also be some
unknown physiological suscepribility – all speculation at this stage. Mute
swans forced to move by cold weather may be more susceptible to AI due to
stress/starvation. But cold weather might also force them to exploit unusual
food sources, possibly bringing them closer to infected material of some
sort.

We must, however, be clear about movements. The swans involved now are most
likely dispersing away from areas that are apparently experiencing extreme
cold in eastern Europe and western Asia. Mute Swans cannot feed on frozen
water bodies and so must move in search of open water. These birds have not
just arrived from Russia, but will have spent some weeks in areas that we
now know have infections in poultry. Furthermore, they are definitely not on
migration to Africa. Migrant mute swans occasionally reach Egypt and
possibly Algeria, but uncommon (Birds of Africa). Egypt does have some feral
mute swans, as does the Eastern Cape of South Africa. Whooper and Bewicks
swans both rarely visit N Africa. The current events, assuming they are
moving away from ice, do suggest that infected birds can travel a some
hundreds of km before dying, or that the infection is present over a wider
area than we thought and they pick it up on arrival at the new venue. The
implications of this are worrying.