Abstract: | The role of estrogen and progesterone in the regulation of reproductive behavior was studied in female ring doves (Streptopelia risoria) under long vs. short photoperiods. The doves held under long (16 hours/day) or short (8 hours/day) photoperiods were treated for 15 days with saline, estrogen, or progesterone, alone or in combination. 7 days after the start of hormone therapy, the doves were placed with reproductively active males for 4 hours/day for 9 days. No difference was seen in egg-laying, courtship or nest-building by control birds under the 2 photo regimes. Ovarian follicles remained small in all doves receiving hormone treatment. Oviducts of doves receiving progesterone alone remained small in the short-photoperiod group but at long photoperiods the oviducts became enlarged. Estrogen stimulated oviduct growth at both photoperiods wheras the combined hormone treatment resulted in greater oviduct development than estrogen alone (p less than .02). Female soliciting and nest-building activity remained low in progesterone-treated doves under short photoperiod but increased rapidly under long photoperiod. Doves treated with estrogen and estrogen plus progesterone performed considerable soliciting and nest-building. No marked tendency was seen for doves under long-photoperiod conditions to be more active in nest-oriented behavior. Copulatory behavior by the female occurred infrequently in all hormone-treated doves. |