You should see if anyone lost a beloved member of their family. For people who lose birds, it is devastating. You have the power to make it better for someone, because it is likely that it accidentally got away and is lost from its home.
If you are able to give this bird everything it needs to be happy and healthy, and nobody has indeed lost their bird/doesnt claim it, then perhaps you may consider keeping it. But please do bear in mind, birds are a huge commitment and responsibility. The proper diet, proper housing and time out of the cage, a stimulating environment with toys and social enrichment. ..all of these are very important things to research and consider...not to mention birds have much longer lifespans than other creatures...some species up to 100+ years. Research this breed and find out everything about it. Research about parrots in general...their diet, behaviors, natural environment...make sure you have the time to nurture this bird and foster a loving, mutually respectful relationship. Remember that nearly (if not every) bird will bite. Never ever hit a bird. Kindness and respect for all living creatures, especially the lovely feathered kind, is one of the most important things.
Also, you will probably need to take it to the vet, for a health checkup. And if you're not going to keep it or invest a little time in looking for its original home, a vet can help reunite the bird with its rightful family.
If the bird is native to the country you're in (indian subcontinent I believe?) It may be wild. I would still say take it to a vet regardless. ..you said crows were chasing it? It could be injured.
It is good that it is eating and drinking. Keeping it hydrated is important. Offer it some greens and veggies (no avocado or chocolate or caffeine) and fruits.
Good luck.