How Do Mother Ducks Know When Their Ducklings Are Hatching?
When a mother duck (or any bird for that matter) is close to the hatching stage, a series of fascinating events occurs within the eggs. The developing duckling begins to squirm and turn inside the egg, eventually pecking through the shell to make its way out. This process is often a fascinating experience for bird enthusiasts and those studying reproductive biology.
The Role of Hatching Movements
In the final 24 to 48 hours before hatching, the chick inside the egg starts to move. These movements are detectable to the parent serving as both a cue and a confirmation that the hatching process is imminent. The navel of the chick draws in the remaining nutrients from the original egg, and as the embryo has grown into a baby duck, the calcium from the eggshell has been converted to bone and flesh, making the shell thinner and easier to break through.
Parental Sensing and Hormonal Changes
The parent bird can feel these squirming movements within the egg and knows that the chicks will soon start pecking their way out. This awareness prompts the parent to sit tighter on the nest. Hormones also begin to flow from the parent’s glands, stimulating a protective and nurturing instinct. For instance, in chickens and pigeons, both parents promote the production of a special substance called pigeon milk, used to feed the hatchling shortly after birth.
Signs of Imminent Hatching
In my experience, I've held many pigeon and chicken eggs near the hatching stage and noticed the subtle movement and tiny pecks from inside. These sounds can be readily heard when holding the eggs to one's ear. A parent duck can also hear the chicks pecking inside the shell, responding to them even before they break through the shell. This interaction is crucial for imprinting, where the newly hatched duckling learns to recognize its mother's calls and behavior.
Discrimination of Dead Eggs
Before the chicks hatch and make their way out, they start pecking from within. However, not all eggs will hatch successfully. Unfertilized or dead eggs may remain at the back of the nest until the parent physically removes them. It's believed that the parent can hear and feel these movements, helping them differentiate between viable and non-viable eggs.
Parental Removal of Non-viable Eggs
For domestic hens, they can usually differentiate between good and bad eggs. They will generally remove any non-viable eggs from the nest, ensuring that only healthy hatchlings survive. This process is crucial for the health and well-being of the hatchlings.
Interactions and Imprinting
Once hatchlings are free from the eggs, their interaction with their mother is crucial. In domestic chickens, newly hatched chicks may take a day or two to fully understand and respond to their mother's calls. This period allows the chicks to imprint, making them recognize and respond to their mother's behavior. This process is also seen in wild birds, although specific details may vary.
Beyond the initial stages of brooding, both domestic and wild birds demonstrate parental instincts that ensure the health and survival of their offspring. Understanding these behaviors can provide valuable insights into avian biology and bird care.
Whether you're a bird enthusiast, a farmer, or a birder, understanding the hatching process and parental care can be fascinating and beneficial.