Their strong bodies and large brains played an important role. Crows can survive in a wide diversity of climates. They are now found on every continent. How did crows spread around the world? Researchers at the University of Washington explain.
The study is in Nature Communications. It details that crows are intelligent tool-using birds. They can solve complex abstract problems and speak a volume of words.
“Not only important to consider not only the ability to get to new places. Also the ability to survive once you get there. Crows diversified because they were very good at adapting to different habitats.” So said Carlos Botero, assistant professor of biology in Arts and Sciences, in a statement.
Crows have longer wings, larger body sizes and larger relative brain sizes compared to other corvids. “A very convenient combination. It allowed this group of birds to colonize and diversify around the world,” the study says.
Longer wings mean greater flight capabilities to disperse around the world. Large brains suggest flexible behavior. They were more intelligent than other corvids, which increased their chances of survival. Their larger body size also gave them a competitive advantage over smaller species.
From hot to cold
Crows experienced high rates of evolution and trait speciation. This led to their rapid expansion across the globe. Arrival in a new environment exposed them to new selective pressures. Adapting to the cold Arctic, for example, required very different strategies and traits.
“New environments favor adjustments in an organism’s phenotype. They facilitate survival and overall performance. That process is often referred to as optimizing selection. “For crows, that meant acquiring new beak shapes that did not exist in any other corvid.
Scientists also found that they increased variation in body size as they colonized new environments. There is no doubt that these abilities explain how crows spread around the world.