BLOOD VALUES OF COMMON CRANES (GRUS-GRUS) BY AGE AND SEASON

1. We studied the blood composition of common cranes (Grus grus) along the wintering period (October-March). 2. Plasma proteins decreased along the winter period whereas plasma urea increased. Both parameters were highly correlated. 3. Plasma levels of uric acid, triglycerides and cholesterol did not change during the winter. Young birds showed higher levels of plasma triglycerides. 4. Red blood cell number, hematocrit and blood hemoglobin content were similar in young and adult birds. Lower values of hematocrit and red cell number were recorded in early autumn. 5. Total white blood cell number did not change during the winter, young birds showing higher numbers than adults. Lymphocyte number decreased from November to March while heterophil counts increased.