Bird Neurology Exam

Birds are incredibly complex pets, and we are only scratching the surface of avian neurology. It’s important when you see a bird come in to your consult room, that you can qualify and ideally localize neurological disease or trauma.

Your neuro exam should include a full physical examination, but will also include:

  • Observation
    • Mentation
    • Posture
    • Movement/Gait

  • Examination
    • Palpation
    • Postural Reactions
    • Cranial Nerves

  • Sensation and pain

Observation
Similar to cats and dogs, you should take a hands off approach and take some time to examine your patient.

Start off at a distance and let your bird relax, or at least as much as possible.

Mentation and movement are very much like dogs and cats (just substitute forelimbs for wings!), the primary difference here is posture.

Birds should have their head and neck upright, if they dont, this could indicate pain or if a head tilt is present, vestibular disease. Circling can occur, usually to the side of the lesion. You can also see nystagmus. which is usually away from the lesion!
Additionally, levels of consciousness occupy a spectrum from
Normal (alert) – as suspected, these birds are normal!
To
Coma – unresponsive, cannot be aroused.

The same principles apply, observe foot position for ataxia and weakness, as well as decreased muscle tone.

Watch for any movement abnormalities, like failure to move wings and avoiding placing weight on one leg.

 
Examination
As you perform your thorough clinical exam you should focus on:

  • Musculoskeletal system
  • Vertebral column
  • Skin

Zooming back in on posture, just like your normal neurological exam, there are postural reactions that can be assessed. Including:

  • Drop and flap  – holding on the perch or legs in hand, quickly lower your bird, they should flap their wings as a proprioceptive response.
  • Placing reaction – move your bird through the air towards the edge of table, your bird should try to place their feet on the table as they approach it. If there is no feet movement, then this is abnormal. There are two methods to test this placing reaction
    • Tactile – with eyes shielded, monitor your birds response to coming in contact with the table.
    • Visual – birds can see the table.
  • Hopping – hold up one hindlimb, then push your bird toward the leg they are standing on. If they are normal, they will hop with the motion on their leg. If not, they will fall over!

Reflexes are very similar to what you know!

  • Patella reflex – challenging but possible!
  • Wing withdrawal reflex – like a pedal withdrawal reflex.
  • Foot withdrawal
  • Vent sphincter reflex – pinch the skin around your bird’s vent, there should be a muscle “winking” response (contraction). If there are nerve reflex abnormalities this will be normal, absent or hyper-responsive.

Cranial nerves can differ from your small animal dog and cat approach, a few specific examples include:

  • Beak tone
  • Menace response
  • Direct pupillary light reflex – as birds have eyes on the side of their head and a complete septum between their eyes. HOWEVER, they do have voluntary iris control, so an absent response to light does not necessarily mean altered mentation.
 

 
Sensation and Pain
If you remember your spinal cord anatomy, your layers from shallow to deep are:

  1. Proprioception
  2. Motor function
  3. Superficial pain
  4. Deep pain

So if your bird can voluntarily move, you don’t need to assess pain!

Good luck, remember your first principles!

Fly to it!

References:
  • Powers, L. Avian Neurological Exam. AAVAC-UPAV Conference. 2018.