Unlike other species of corvids which mostly only colonize a single continent, raven and crow species have a wide distribution on a planetary scale.
Biologist Joan Garcia-Porta and colleagues associated with Washington University in St. Louis, USA, have determined that the success of these birds depends on their longer wings, larger bodies and brains. than those of their corvid cousins.
- Long wings allowed them to fly longer than other corvid species. They are thus better dispersed throughout the world.
- Their body size also gave them a competitive advantage over smaller species, helping them to establish themselves in a new environment.
- Possessing a large brain has given these species an intellectual advantage over other corvids. They were able to adapt to a new environment, which increased their chances of long-term survival.
To establish these three characteristics associated with their success, the team analyzed corvid specimens from museums in Europe and the United States. The birds of the genus Corvus consistently featured longer wings, larger bodies, and larger brains than their corvid cousins.
It had already been established in the past that the length of the wings of crows and ravens allowed them to fly farther and to access new habitats more easily. But the current study shows that their large bodies and large brains allowed these species to survive in the new areas they were reaching.
When we think of a species’ ability to spread, it’s important to consider not only the ability to reach new places, but also the ability to survive once there.explains Carlos Botero, professor of biology at the University of Washington in Saint-Louis.
” Our work suggests that ravens and crows quickly colonized new spaces because they were particularly good at adapting to different habitats. »
It is therefore their great behavioral flexibility that allowed these birds to survive the initial periods of maladjustment. Subsequently, the ravens and the crows experienced
high rates of trait evolution. During this evolution, new species have differentiated themselves from the original species, with which they can no longer even reproduce.
Arrival in a new environment has exposed them to new selective pressures, which often promote changes in an organism’s phenotype that facilitate survival. For example, in the case of ravens and crows, new beak shapes appeared that did not exist in any other corvid.
The details of this work are published in the journal Kind Communications (New window) (in English).