Photoperiod Experiments on the American Robin

The American Robin of southwestern British Columbia was tested in captivity under four light regimes: LD 8:16, 12:12, 16:8, all under artifical light, and natural daylight increment from LD 12:12 to 16:8. Robins under the latter two regimes gained in gonadal weight and in follicular and seminiferous growth, and the males developed spermatocytes and, under natural light, spermatids

D. Lynne Kempel and J. Mary Taylor, Northwest Science, Vol. 56, No. 1, 1982