During the COVID-19 pandemic the world stopped completely. Something that scientists have named ‘anthropause‘: a sudden silence of human activity that left many of us confined at home and that even affected nature. This effect was so extreme that even a species of bird changed its beak as science has now seen.
The study. Although in the past we saw some disorders in nature, such as the appearance of wild boars in Barcelona or dolphins in Venetian ports, now a team from UCLA has gone further. a study published in PNAS indicates that a population of urban birds modified his physical anatomy in record time.
The objective they had was to survive the absence of humans at that time. But the most surprising thing is that when everything returned to normal and humans began to go outside, the birds returned to their original beak.
The dilemma. To understand the discovery, you first have to know the protagonists: the dark eyed juncos. Some small birds that are very common in the field of the University of California in Los Angeles.
Before 2020, these birds had short, wide beaks. Something that makes perfect sense, since they were in an environment full of students and, therefore, His diet was based on leftovers. that were left This is why it needed to have a robust beak to handle these ‘artificial’ foods. In contrast, their relatives that live in wild forests have longer, thinner beaks, designed like precision tweezers to search for insects and seeds hidden in vegetation.
The pandemic. When UCLA closed its doors in 2020 and the students disappeared, so did the easy food. And this was where the university researchers saw a unique opportunity to study what happens when you eliminate humans from the ecological equation.
The results. What was seen in this case is the new generations of reeds that were born precisely in this time of ‘loneliness’ they developed longer and thinner beaks. All this because since there was no human garbage, they had to behave like wild birds again, foraging on the ground and looking for food alternatives.
But what was most fascinating happened after the reopening. As soon as students (and their snacks) returned to campus in 2022, the morphology of the peaks quickly reverted to the urban form with a short, thick shape. This is ultimately an extremely rapid evolutionary change that is very rare to see.
A change of mind. What makes this study so relevant to the scientific community is the speed of the field. Generally, we think of evolution as a process that takes thousands of years. However, what we observed here suggests that urban species have a much more elastic capacity for adaptation than we believed.
Since it’s not just the peak. Previous studies by the same team had already noted behavioral changes: during the pandemic, these birds lost their fear of humans, becoming less aggressive and more curious, although that behavior also readjusted with our return.
Its importance. This case is a brutal reminder of our ecological footprint. We don’t just alter the climate or the landscape; our mere presence and our waste acts as an evolutionary force that shapes the biology of the animals around us like these birds.
The UCLA rushes have taught us that nature is not static; It is a dynamic system that reacts to our habits almost in real time. The question that remains in the air is: if a couple of years of silence changed the shape of a bird, what other invisible changes are we causing without realizing it?
Images | Vincent van Zalinge David Mitran
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