Variation of the Reed Bunting (Emberiza schoeniclus) Body Condition and Haematological Parameters in Relation to Sex, Age and Season

Abstract

The body condition and haematological parameters of birds are influenced by a multitude of factors. Here we investigated body mass, fat scores, ratio of heterophils and lymphocytes (H/L), red blood cell count (RBC) of reed buntings (Emberiza schoeniclus), expecting differences between spring and summer (different physiological states/energy demands in breeding/post-breeding periods), sexes (different parental duties) and age groups (different experience/social status). Fat scores and size-corrected body mass were similar in all the groups. Adults in spring had higher H/L than in summer, which may have been due to reproduction-related stress or the seasonal elevation of glucocorticoids. The lower RBC and H/L in adults in summer were associated with their complete moult. Lower H/L in adults in summer compared to immatures may have resulted from their lower stress level (greater experience/higher social status) or a complete moult. The H/L ratio was similar in both sexes, despite their different parental duties.