Male-to-female aggression in cage-housed common pheasants (Phasianus colchicus) during the breeding season was not related to male plasma testosterone level

ABSTRACT1. The aim of this study was to investigate if male-to-female aggression of common pheasants in the course of the breeding season was related to the concentration of plasma testosterone and/or other biochemical plasma indicators in male pheasants housed in breeding cages. The influence of season on the concentration of testosterone and biochemical indicators was also investigated.2. Males were divided into non-aggressive and aggressive groups during the breeding season based on ethological evaluation. At the beginning, in the middle and at the end of the breeding season, a blood sample was taken from all males on the same day and the concentration of selected biochemical indicators and the total circulating testosterone in the plasma were determined.3. Male-to-female aggression during the breeding season of pheasants was not influenced by the total plasma testosterone of males.4. The concentration of total plasma testosterone in males decreased gradually during the breeding season.5. Male-to-femal...