Off the coast of Spain, in Salvora Island, thousands of eggs of yellow-legged gulls are found spread out on the sands from the midst of April up to late July. They create a beautiful kind of noise that is an exchange between the sound of white wings flapping in courtship and those plaintive calls for chick-feeding tasks. And when one of the older birds notice a predator in sight, usually a dusky-coated mink, the chorus of noise shifts again to characterize something that sounds alarming.
Such type of acoustic cues reaches not only the hatched but those in the embryos as well. In 2018, researchers discovered that when the gull eggs hatch, the ones that have been exposed to the sound of the alarm were able to crouch and hide from the predators faster than those who have not heard the cue for alarm.
There are a few other species of birds, including fairywrens and zebra finches and quails, are known to relay cues of danger about their immediate environment to their youngs in eggs. This is to help prepare the hatchlings as to what they could expect as they learn to fend for themselves.
However, these embryos are not only receiving such type of survival wisdom from their parents, but they get it from the environment as well.
A new study published in the journal Nature Ecology and Evolution, reveals that embryos are also getting cues from nearby unhatched siblings.
"Paying attention to the cues sent from the outside is important for a hatchling to survive," said JoseNoguera, lead author of the study and an evolutionary ecologist from the University of Vigo, Spain.
Embryos who are able to learn from before they hatch can develop traits that will help them survive the wild. They are at an advantage to avoid predators while building their circle of birds they can interact with. Later on in life, they will be able to build their own nest in areas where there are warmer temperatures, he added.
"It's a rough and tough world out there," Mr. McGowan said. 'Most young birds don't grow up to be adult birds. The even sadder part is that those birds who are supposed to be producing the young no longer produce offspring, too afraid that they might not survive the predation.
The game of Natural Selection can be quite a monstrous game. "If you can get a leg up by listening to one's sibling, then you are surely protected, even for yourself.
