Isolation from conspecifics in young, precocial birds prehighly predictable variations in terms of call occurrences dictably induces distress vocalizations (DV) and andro- (Guyomarc'h and Thibout, 1969;Minnich and Bernroider, sepp et al., 1980, 1989Minnich and Bernroider, 1995; and their relevance to the temporal evolution of DV and Waldhör and Bernroider, 1994; Mench and Ottinger, Pniewski, 1978; Schumacher and Balthazart, 1985). Lesion cleus (ICo) as the main motor control area that is common these findings, we suggest that organizational steroid to the expression of DV and CR (Potash, 1970). Further effects change the characteristic duration of isolationevidence that CR develops from a testosterone-induced induced vocalizations and these effects appear to be transition from DV to CR in the juvenile bird also stems manifested at the level of opioid-receptor distribution.