This study is an important part of efforts to care for the welfare of this bird as once it is known where it goes and how long it stays in various places then we can start to take action to reduce the hazards - natural and man made - that these birds come across on their journey.
In order to track these birds nine were given a radio transmitter implant and the re-released. The signal from these implants can be picked up by satellite telemetry and the location of each bird recorded at regular intervals. The locations are presented for each bird here - remarkably viewers can follow the route as the bird migrates.
This is usually a symptom of a bird that has become stressed by lack of food/poor food/exhaustion/cold/age weather as under these condition their immune system tends to work less well and they can become infected - much as happens in humans when their immune system fails. Perhaps in this case exhaustion was a key as it was a member of the group that seems to have migrated the furthest?