Skip to content

A Missing Tracheal Ring in a Eurasian Sparrowhawk

Research · Anatomy & morphology

A female Eurasian sparrowhawk (Accipiter nisus) was missing its 45th tracheal ring, a finding revealed by detailed imaging of the bird after death. The authors describe it as the first reported congenital absence of a tracheal ring in a wild bird examined using micro-computed tomography (micro-CT).

Tracheal rings are cartilage supports that help keep the airway open. The researchers used limited dissection and micro-CT imaging to examine the bird’s trachea. The scan showed no other skeletal abnormalities. The bird’s origin and cause of death were unknown.

A wider gap in the airway support

At the missing ring, the space between neighbouring rings measured about 1.0 mm on one side and 1.3 mm on the other. For comparison, the average spacing between rings elsewhere in the trachea was about 0.44 mm. The missing support therefore left an unusually wide gap in the structure that helps hold the airway open.

The scan showed no collapse of the trachea. But a postmortem image cannot show how the airway moves during breathing in a living bird. The authors suggest that the gap could make that section less stable, but this case cannot establish whether the sparrowhawk had breathing problems.

The trachea also helps shape birds’ vocal sounds. The authors note that an abnormality affecting airflow or sound resonance might influence calls, which can matter in territorial behaviour and reproduction. No effect on this bird’s calls was observed, however. The case documents an unusual anatomical finding; whether it had consequences for the individual remains unknown.

Sources and image credit

  1. Congenital deficiency of a tracheal ring in a Eurasian sparrowhawk (Accipiter nisus): a micro-computed tomography case reportPrimary journal article; full text identified in the supplied fact packet.

Image: A female Eurasian Sparrowhawk (Accipiter nisus nisus) stands on the ground among reeds and vegetation. Photo: Charles J. Sharp / Wikimedia Commons, CC BY-SA 4.0. Representative photograph. · CC BY-SA 4.0 · Source

About this content: This story was produced with AI assistance within an editorial workflow developed by Wildlife Vagabond. Editorial responsibility remains with Wildlife Vagabond.How AI is used

Anatomy & morphology

SPECIES IN THIS STORY

Species in this story

Eurasian Sparrowhawk Accipiter nisus Explore species

Independent research and conservation news archive

Did you find this information useful?

Wildlife Vagabond is independently built and maintained. Voluntary support helps cover source verification, hosting and continued work on research and conservation news.

Support Wildlife Vagabond

The news archive will remain freely available.