Geese do not relocate their eggs once incubation begins. After laying a full clutch, the eggs remain fixed to the nest site. However, the female goose frequently adjusts and rolls the eggs within the confines of the nest bowl itself. This constant, gentle manipulation is a routine, non-negotiable part of successful development.
Egg Rolling and Adjustment
The movement of the eggs is a precise and repetitive behavior primarily performed by the female parent, though the male gander may occasionally assist when the female leaves the nest. This is a subtle adjustment, involving the goose using her bill and neck to gently nudge and roll the eggs a short distance. The action is not a random pushing but a deliberate rotation around the egg’s axis.
The frequency of this internal nest adjustment is quite high, occurring several times every hour throughout the 28-to-30-day incubation period. For instance, studies on Canada geese have observed the parent turning the eggs approximately 1.2 times every hour, translating to nearly 30 full rotations each day. This consistent movement ensures that all eggs are equally exposed to the parent’s brood patch, a featherless area of skin that provides direct heat transfer.
This routine turning differs completely from moving the entire clutch to a new area. The parent’s actions are focused solely on optimizing conditions within that small, confined space. The goal is to redistribute the eggs relative to each other and the heat source, not to transport them.
Biological Necessity of Turning Eggs
The necessity of egg turning is rooted in three primary developmental requirements for the growing embryo. The first is to prevent the developing embryo from adhering to the inner shell membrane. The yolk and embryo tend to float upward toward the warmer part of the egg, and without rotation, the delicate embryonic tissue would become permanently stuck to the shell, which would be fatal.
Turning the eggs also guarantees a uniform temperature distribution across the entire egg surface. The brood patch provides concentrated warmth, but rotation ensures that every part of the egg receives equal heat, supporting steady and regulated embryonic growth. This is particularly important for large goose eggs, which have a greater volume to heat.
Furthermore, egg movement is closely tied to the proper utilization of the albumen, which serves as a major nutrient and water source. The turning action helps redistribute the egg’s internal contents, making the albumen fully accessible to the embryo as it develops. This movement also facilitates gas exchange, allowing the developing embryo to breathe by regulating the movement of gases through the porous shell.
Response to Nest Disturbance
When a goose nest is severely disturbed or compromised, the adult pair will not attempt to relocate the entire clutch of eggs to a safer location. Geese are highly devoted to their chosen nesting site once incubation has begun. Attempting to physically roll or carry the large eggs a significant distance would expose them to temperature fluctuations, potential damage, and predators.
If the nest is destroyed early in the season, such as by flooding or a predator attack, the female will typically abandon the existing eggs and may attempt to re-nest nearby. If the eggs are removed or destroyed by external factors, the geese will often leave the area within a few days, recognizing the loss of their clutch. The energy cost and risk of trying to move a full clutch of eggs far from the original, familiar site is too high for the parent to undertake.