Is it permissible to mate a goldfinch with a canary to produce beautiful-sounding, sterile offspring?

There is no objection to the hybridization of animals, such as breeding a donkey with a mare to produce a mule. Many scholars have permitted it, while others have disliked it. Evidence for its permissibility is what Imam Ahmad narrated from Ali (may Allah be pleased with him), that a mule was gifted to the Messenger of Allah (peace be upon him). When asked about it, he said: "A donkey is bred with a mare, and this comes out between them." As for the prohibition mentioned in the hadith regarding the hybridization of horses and donkeys, Al-Tahawi interpreted it as specific to Banu Hashim due to their scarcity of horses, because horses yield more reward than mules.