"Strokes," caused by the sudden rupture of a blood vessel in the brain

Bird is flying erratically, unable to balance, falls from the perch etc

Extremely difficult to diagnose in Canaries.

Keep the bird in a small cage in a quiet dull but warm location. Avoid bright sunlight. Make sure there is plenty of Canary seed and water. If the bird is to survive it will recover quickly.

Do NOT breed with birds that you know have had a stroke.

"Strokes," are rare. It's more likely your bird is suffering from a metabolic problem such as low blood sugar or low blood calcium, ingestion of a heavy metal such as lead or zinc, or a disease of the central nervous system including tumours.
Many of these conditions are reversible if quickly diagnosed and treated. Unfortunately, many birds that suddenly collapse die before anything can be done to help them. If your bird is highly prized see a vet

Published June 2009