Rapid stress-induced inhibition of plasma testosterone in free-ranging male rufous-winged sparrows, Peucaea carpalis: Characterization, time course, and recovery

► We researched the endocrine effects of acute stress in a free-ranging male songbird. ► Capture and handling decreased plasma testosterone (T) within 10 min. ► The decrease in plasma T persisted for at least 6 h after release on site. ► Plasma T decreased relatively more in birds with high than low plasma initial T. ► Acute stress increased plasma corticosterone but did not influence plasma LH.