We saw this black swan at Melbourne City Marina. When I contacted wildlife rescue I was told it was a tag. I felt the bird was unable to compete for food as the tube inhibited movement.
This swan was definitely disadvantaged foraging for food. I feed swans salads and the small family it was with was quick to get the floating leaves often right under this swans beak because it was unable to move as quickly. Surely if this bird is indeed being monitored daily or weekly the disadvantage that I observed would have been noted and the tube tag removed.