Influences of sex hormones on the loud and soft warbles of male budgerigars

摘要: Abstract Does a male's performance of loud and soft warble his possession active testes result coincidentally from the vocal stimulation by others in flock or does one these resultant features influence occurrence other? This study investigates influences sex hormones upon extent to which behaviour other males may possessing different internal (hormonal) states. Each was recorded while he deprived social stimuli both before during hormonal treatments. During treatments, each male also could hear taped 2-hour concert performed males. Intact were injected with either pregnant mare's serum (PMS), testosterone placebo solutions. Oestradiol cypionate PMS administered castrated The data show that (1) threshold for performing without are significantly lowered androgens but not solely influenced gonadotropins. (2) Hearing seems stimulate warble, it seem warble. (3) Two factors, individuals, increase tendency perform warble; factors complement their action(s). (4) In absence stimulation, injections oestradiol However, provoke any definitive pattern response status warbles as sexual behaviours is briefly discussed.