Scientists explain how crows and ravens are taking over the world

By Joe Morgan via SWNS

Crows and ravens have "taken over the world" - living in both the Arctic and tropical rainforests, reveals new research.

Large brains and bodies, as well as the ability to diversify, mean they have what it takes to colonize across different habitats, scientists say.

Specimens taken from across the globe have shown crows and ravens, unlike other birds which stay within single continents, have rapidly expanded worldwide.

Researchers that the secret is their great flying ability, longer wings, and big brains which means they are smarter than other Corvids like jays or magpies.

Crows and ravens experienced high rates of trait evolution and speciation as they adapted to the many different environments they encountered during their rapid expansion across the planet.

This might have meant increasing body size variation or acquiring new beak shapes which meant they were able to survive.

Dr. Carlos Botero, associate professor at Washington University in St Louis, said: “When we think about processes of global diversification, it is important to consider not just the ability to reach new places, but also the ability to survive once you get there.

"Our work suggests that crows and the ravens diversified both quickly and widely because they were particularly good at coping with different habitats.

“We are excited with these new insights on how these birds were able to do things that even close relatives did not.

“It truly seems that their incredible behavioral flexibility may have played a major role in allowing these birds to survive initial periods of maladaptation and hang in there long enough for selection to catch up and produce a range of new species in the process.

“These new environments often favor tweaks to an organism’s phenotype that facilitate survival and overall performance. That process is often known as optimizing selection."

Dr. Joan Garcia-Porta, at the University of Barcelona, added: “We hypothesize that these three very convenient combinations of traits are what allowed this group of birds to colonize and diversify across the world.

"Thanks to these amazing birds, we now understand a bit more the processes by which animals rapidly expand across the planet and how this geographic expansion translates to the production of new species with new morphologies.”

The study was published in the journal Nature Communications.