Crows have apparently been fractured into two different populations a few hundred thousand years ago, which later began to separate in two standalone groups. Experts have estimated that the two different species were similar, apart from some small variations in the body and the sounds they made.
At least, that is what they believed. It currently seems that, after encountering the speciation process over many years, these two crow groups, the Northwestern and the American crow, have begun fusing back into one, as per some new genetic information.
A ‘New’ Species of Crows
The crows have been crossbreeding across a 900-kilometer-long region of the Pacific Northwest. The research depicts more intricate evidence of what represents a ‘new’ species.
“It means that speciation isn’t a one-way process,” Dave Slager, the study’s first author and a Ph.D. candidate in biology at the University of Washington, said. “It can even go in reverse, sometimes.”
Experts have observed the two crow species since the year 1858. The Northwestern crow is a bird of Pacific Northwest beaches and wetlands, a bit smaller than the American crow with a low-pitched voice, ornithologists and birders have stated.
The team of researchers from the University of Washington, the Burke Museum of National History and Culture, and the U.S. Geological Survey collected samples from crows from both species. They assayed DNA from the birds’ cellular core and mitochondria and considered information from genetic collections they created in order to estimate whether the crow genomes proposed, isolate evolutionary backgrounds of the two species, as well as how frequent the birds hybridized.
The birds, however, started crossbreeding on an area that is seven times larger than the usual hybrid region between species pairs, the study says. Even though separate groups usually crossbreed over a restricted area, and though hybrids are typically not favored via natural selection, this was not the case here at all. The genetic information showcased the fact that the crow hybrids were components of hybrid generations dating back numerous lineages.
Nature’s Cryptic Ways
A scientist who was not part of the researching team, Martin Stervander, a postdoctoral evolutionary biologist at the University of Oregon, said that the paper was incredibly exciting.
“Over the years, many have claimed observations of consistent differences between American and Northwestern crows, but scrutinization has revealed that this has partly been based on people perhaps rather wanting to find consistent patterns,” he said.
However, he also indicated that it would be useful to analyze the appearances of these birds at the same time as their genetics, in order to determine which attributes each lineage was handing to the hybrids.
Slager did not clearly say whether he believed the two groups should be merged into one species of remain separate populations, since that depends, apparently, on the American Ornithological Society. However, he indicated that across the breeding zone, you could not tell the two species apart because they are probably no pure Northwestern or American crows.
Animals keep showing people that our fabricated notion of species is defective and doesn’t line up with what it takes place in nature.