Mule
This bird is an intriguing hybrid between a canary and a European goldfinch and has been artificially bred since the Victorian era when they were famed as songbirds.
They are famous for singing the best of all birdsongs and for this reason, served as cage birds back in the day. Now not as common as they were in that era, still they are bred and kept by aviculturists. These birds, like so many other hybrids, are sterile despite still being bred for captivity.
