RSPB Ynyshir satellite tracking of white-fronted geese
Electronic tags fitted to one of Europe's rarest birds have revealed "vital data" that could help safeguard the species, researchers have said.
The RSPB estimates the population of Greenland white-fronted geese at its Ynyshir reserve near Machynlleth, Powys, has declined by 83% since 1990.
Very little is known about the birds.
But a study, funded by the Welsh Government, has provided new insights described as "a glimmer of hope".
The RSPB's Tom Kistruck told BBC Wales' environment correspondent Steffan Messenger what the trackers could tell them.