Just some food for thought. I am convinced that it was people that brought Elijah food, but I will not rule out that if God so ordered birds to bring Elijah food, it was so. I want to add my observations that lead me to believe what I do.
First, We are all aware of the fact that there is strong proability that things were added, changed or removed by those who either copied or translated original texts. We also know that there were ancient Hebrew words were that were so similar in spelling to others and that often, just the slightest error in copying could easily result in the wrong word being spelled. Since all humans are flawed and do make mistakes, this has to be considered. There are a number of factors that could cause a copyist to make a mistake, headache, physically ill, lighting, distraction, stress, interruptions, eyesight, personal interpretation etc. The problem is if one scribe were to get a word wrong, and if not caught, his work, with an incorrect word in place, would later be copied by others. I am not aware of one manuscript, seperated by dozens or hundreds of years, being an exact duplicate of earlier manuscripts.
Second, there are other disputed words that have been debated over for hundreds of years with no agreement between scholars and linguistics. For Example, was Isaiah writting about a virgin or young girl in Isa 7:14? Was Rahab a prostitute or an inn keeper?
Third, Scripture reads that the ravens brought bread and meat in the morning and in the evening. It is possible that the ravens could have hunted small animals to bring Elijah meat, but where would they obtain bread? Ravens would not have been able to make bread, which means that they would have had to swoop down on people and snatch bread. If the ravens located in that geographical area were in the habit of stealing food from people, that those people would have protected their food from being snatched by ravens. While ravens do hunt, they also eat carrion.
Fourth, by the phrasing of the words and real life, it is clear to see that the food brought was prepared food, ready to eat. There is no mention of Elijah preparing the meat brought to him, or of him preparing and baking bread.
In the morning and evening sounds a lot like a somewhat scheduled time, based on the practice of mankind throughout history of normally preparing food at the same times every day.
Fourth, God said He commanded the ravens to feed Elijah. There are no other verses in the Old Testament about God "commanding" animals. Every time God "comnandes" it is always to people. When it came to nature, it is always that God either caused an event to happen or He sent it.
Fifth, IKings 17:8-9, God commanded a widow to feed Elijah. Again, Elijah does not have to prepare his food. In 1Kings 19:5-6, we see an angel prepares a cake for Elijah to eat and provides water for Elijah to eat.
As I previously stated, I am not going to rule out that God used the birds known as ravens to feed Elijah, but to me, this wouldn't make sense. When one studied Scripture, one has to compare Scripture with Scripture and one has to try and figure out how any event in Scripture ties in with the whole of Scripture.