Egg–laying of Ducks as an Enforced Relaxation Oscillation

Abstract

THE formation and deposition of a bird's egg can be described as a relaxation process¹, the egg material being piled up gradually and released suddenly. The sustained production of eggs can then be regarded as a series of relaxation oscillations. In an undisturbed relaxation system discharges take place when the accumulating material (energy) reaches a certain level, but the length of period may change if the stream of material (energy) varies. If a bird were an undisturbed relaxation system, eggs of fairly constant size would be expected at varying intervals according to the amount of food available. This is not the case in ducks, where eggs of varying size are deposited regularly in the morning on consecutive days, sometimes for months, with pauses of one, seldom two or more days, between each clutch.