The way evolution equips species to deal with their enemies is often surprising. It’s not just about the camouflage of their physical appearance, it’s also about sounds can also help birds protect themselves from predators. This is the case of a very common species in Spain that imitates the sounds snakes make when they see their nests in danger. This was confirmed by a group of scientists after long research.
Family paridaeEasy to spot in forests and other habitats, including species well known in Spain such as the great tit and blue tit, They emit hissing sounds similar to the snoring of snakes. to defend their nests and thus scare off their predators.
Study published in the journal Current Zoologysuggests that this defense mechanism may have evolved in birds due to the help it provides to make a snake-like sound. And like many people, many birds are afraid of snakes and vipers.
A puzzling case of acoustic mimicry, and a curious fact, it appears to be exclusive to women, the researchers noted.
How does a small bird imitate a snake?
“When a predator approaches the nests of certain udders, such as udders and udders, the birds respond by emitting a loud snoring, stretching their heads and flapping their wings”, Explains Diego Gil, a researcher at MNCN who participated in the study.
“We wanted to confirm the acoustic similarity between these snores and those emitted by snakes. To do this, we compared more than 40 records of six species of the family. paridae with the snoring of 14 snake species belonging to their families. vipers, elapidae Y snakes. What we found was that the acoustic profiles were very similar, but only in the case of snoring that propagated inside the nest, as other alarm vocalizations did not show this similarity,” says the researcher.
This is the popular big tit situation. When a predator approaches its nest, the female lifts her head, fluffing her head feathers, “bulging” her eyes and raising her wings. Again and again, the bird soars above its tarsi, giving off an explosive hiss as its head snaps forward like a snake and shuts its jaws. Simultaneously, the wings glide downward, often striking the sides of the nest cavity, the tail fans sticking out, and the outermost tail feathers prominently displayed.
a working system
In the second phase of the study, the researchers asked themselves the same question. They wanted to check whether the sounds were really effective in the face of the arrival of a predator or if it was a useless attempt by the birds to defend their young. They used a curious character to prove it.
“We are training a few specimens of Swinhoe’s squirrel (Tamiops swinhoei hainanus) often feed on the eggs and young of these birds, going to a food source to feed. Later on, We listened to recordings of alarm sounds to observe their reactions and confirmed that when this happened the animals avoided approaching the food.Gil points.
“The results of this study show that the snoring that birds emit in their nests is the result of acoustic mimicry and functions as effective defense mechanisms,” admits Diego Gil.
This makes sense. Faced with these brutal visual and auditory threats posed by such a masterful snake mimicry, most predators retreat just in case. Y this increases the chances of survival of the snake-like bird.
Because birds and snakes do not share a common direct ancestor, the researchers think this behavior may have evolved by evolutionary convergence. This means that calls that mimic the sounds of snakes have been selected in birds over tens of thousands of years, thanks to evolutionary changes.
However, it happens that not all chickens have this behavior. There are not even examples of the same species. According to this study, in an identical population within the same habitat, there are specimens that mimic snakes and those that do not.
Reference work: https://doi.org/10.1093/cz/zoab001
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Source: Informacion
