Influence of pinealectomy and photoperiod on courtship and nest-building in male doves.

Sham-operated male doves displayed greater nesting activity under long days (16L:8D) than under short days (8L:16D). This difference was abolished by pinealectomy--the activity of long-day pinealectomized birds dropped to a level comparable to that seen on short days. Removal of the pineal had no effect under the short photoperiod. These results are not due to changes in peripheral androgen production as castrated, testosterone-implanted males also exhibited higher levels of nest-building on long days if sham-operated, but not if they were pinealectomized. Neither treatment had a significant effect on courtship or copulatory behavior. It is suggested that the pineal mediates the stimulatory effect of long photoperiods on hormonally-induced nest-building in doves.