STUDIES ON THE PHYSIOLOGY OF REPRODUCTION IN BIRDS

Abstract

Basal metabolism of incubating ring doves was measured at 20[degree] and 30[degree] C, and at a normal or "resting-stage" of the reproductive cycle for comparison. Measurements (74) made at 20[degree] C. indicate that basal heat production of [male][male] is decreased by 10% from a normal resting-stage value after brooding eggs for 10 to 13 days, and that no change occurs in the metabolism of their [female] mates. Similar measurements (52) made at the so-called "zone of thermal neutrality," 30[degree] C, indicate that the basal heat production of brooding [male] ring doves is increased by 6% and that of their [female] mates is not measurably changed. Evidence is cited in favor of view that the results of the 20[degree] measurements represent the true effect of the incubation factor. The results obtained question the suitability of metabolism measurements made at the "zone of thermal neutrality" when the object of measurement is to disclose the influence of one or another factor on the current basal metabolism.