ABSTRACT
The hemogram of an avian would be expected to display variations from season to season. The factors that impact on the blood picture of a bird during a given season are both variable as well as numerous. The blood pictures of feral Columba livia the pigeon and wild Parus major the great tit were studied during the four seasons of a year. The observed hemoconcentration was proposed to reflect a natural phenomenon developed to cope with the natural water shortage during the hot summer months. The sparrows underwent molting during the study period and presumably this should have had some impact on the erythropoietic profile. Mean hematocrits of 20 pairs of caged indoors, captive-bred Falco sparverius American kestrels sampled over an 11 month period at the Macdonald Raptor Research Centre, McGill University, Quebec, Canada revealed significantly different levels between the winter maximum and the minimum summer values.
