Poultry Judging Practice Test

Which muscle is primarily responsible for the flight ability in birds?

1. Pectoralis major

2. Pectoralis minor

3. Supracoracoideus

4. Latissimus dorsi

The correct answer is: Pectoralis major

The muscle primarily responsible for the flight ability in birds is the pectoralis major. This large muscle is essential as it powers the downstroke of the wings during flight, generating the force necessary for lift. When the bird flaps its wings, the contraction of the pectoralis major pulls the wings downward, allowing for ascent or forward motion. While the pectoralis minor and supracoracoideus contribute to the wing movement—specifically aiding in the upstroke of the wings—the primary force for the downstroke, which is crucial for flight, comes from the pectoralis major. The latissimus dorsi has various roles in movement but does not specialize in flight mechanics like the pectoralis major. Thus, understanding the role of these muscles helps clarify why the pectoralis major stands out as the main muscle for flight in birds.