Hematological parameters as indicators of health of three species of thrushes in subtropical Andean Forests

Hematological evaluation is a useful tool to deduce the health condition of birds. We worked with T. rufiventris (resident), T. nigriceps (a latitudinal Austral migrant of the Neotropics) and Catharus ustulatus (a latitudinal Neartic migrant) in the Selva Montana of Yungas, Tucumán, Argentina. From blood smears, we determined hematocrit, differential leukocyte count, and the relationship between heterophilic leukocytes and lymphocytes (H: L) as a hematological measure of stress. For T. rufiventris, T. nigriceps and C. ustulatus, we reported respectively: 1) Hematocrit average ± DS: 47.09 % ± 5.10; 46.86 ± 8.15; 46.41± 4.18. 2) Differential count of leukocytes: Lymphocytes (72% ± 13.10, 74.01% ± 12.21, 79.58 ± 13.46), Heterophiles (18% ± 9.89, 18.29 ± 11.71, 9.97 ± 8.13), Eosinophils (8% ± 5.64, 4.15 ± 2.59; 5.41 ± 5.76), Monocytes (2% ± 1.41, 3.54 ± 2.47, 5.04 ± 4.19).3) H: L average and range: 0.29 (0.03-0.73), 0.28 (0.05-0.73), 0.15 (0.03-0.53). At an interspecific level, the similarity of hematological values did not show a differential investment in the production of blood cells. However, variations in the H: L quotient in the intraspecific level could be indicating a process of chronic illness or stress, affecting the general health of the individual and the population in the case of infectious agents. The results obtained are useful as reference values for the species analyzed in the region to evaluate the health condition of species from the subtropical Andean forests.