Which one of the following is NOT a symptom of aspergillosis in hawks?

Weight gain is not a symptom of aspergillosis in hawks. Aspergillosis is a fungal infection that primarily affects the respiratory system of birds, including hawks. Symptoms of this condition commonly include ruffled feathers, which indicate a state of distress or illness, and difficulty breathing, as the infection can cause respiratory issues. Additionally, hawks may experience trouble eating due to respiratory distress or other health complications related to the infection. Weight gain, on the other hand, would typically suggest good health and adequate nutrition, which contradicts the presence of a serious infection like aspergillosis. Therefore, the absence of weight gain as a symptom highlights the seriousness of the disease and the overall health decline it causes in affected individuals.