Two experiments were conducted to determine the ability of albino Japanese quail intruders to elicit serum corticosterone responses in established populations of wild-type (W-T) quail. In Experiment 1, W-T quail were mixed with albino strangers and blood sampled prior to (T0) and 2 hr after (T2) mixing. A second W-T group, serving as a control, was bled at these same times but was not subjected to albino intrusion. In Experiment 2, a similar protocol was followed, except albino treated and control quail were not bled at T0. Blood samples were assayed for their serum corticosterone content by radioimmunoassay. The incidence of headbanging behavior by W-T quail from T0 to T2 was also determined. Both control and albino treated W-T quail exhibited significantly elevated mean serum corticosterone levels at T2 when compared to their T0 hormone levels. However, when the quail were not bled at T0, a significantly higher mean plasma corticosterone level was found at T2 in albino treated wild types in comparison to control treated quail at this time. Although percent of individuals headbanging was similar in both control and albino treated W-T quail handled at T0, albino quail intrusion produced a significant doubling in the incidence of headbanging by W-T quail not previously handled. Serum corticosterone and headbanging behavior were not correlated. Collectively, these data would appear to indicate that albino quail intruders serve as effective nonspecific systemic stressors to W-T quail, provided the latter are not handled beforehand.