Sour crop specifically affects which part of a bird's anatomy?

Sour crop is a condition that specifically impacts the digestive system of birds. It occurs when food ferments in the crop, which is a part of the avian digestive tract. The crop is a pouch located at the base of the esophagus that stores food before it moves into the stomach for further digestion. When a bird has sour crop, it often has an accumulation of undigested food and can develop a foul-smelling discharge due to fermentation, which is why this condition is directly associated with the digestive system.

Understanding the anatomy and function of the crop is crucial for anyone involved in avian care, as recognizing the symptoms of sour crop can help in implementing timely treatments to prevent further health complications for the bird. Other anatomical systems like the plumage, skeletal, and nervous systems are not involved in this specific condition.