The coyotes responding does a few things for you:
1. It lets you know they are in the area. This is important for obvious reasons, but the most important for me is it helps you have confidence in the area you hunt. Keep in mind though, just because the coyotes are there it does not mean they will come to the call. Don't get frustrated and think you are doing anything wrong. I have called at coyotes I can see in a field and had them just keep mousing. Talk about drive you crazy! You never can tell what a coyote will do when called at.
2. It lets you know that you got their attention. For whatever reason you have caused a reaction from the coyotes. This is good on one hand, but again it can get frustrating if they don't show for whatever reason.
3. It lets you know what kind of area that particular group of coyotes prefers. This will help you to know what types of terrain to target in that area.
I have had mixed results when I have had coyotes respond vocally to my calling. Sometimes one comes, other times one doesn't. I personally think this is due to the individual coyote, and it may have little to nothing to do with the caller. I do know I have shot more coyotes and not heard vocal responses than the times they have howled at me.
I have called in coyotes with bird distress, as well as cottontail distress and fawn distress. I think the coyotes will respond depending on what it wants. I do not think a coyote has a "memory", but I do think in pressured areas they relate certain things to danger, human scent for example. This is another reason I will alternate calls/sounds in a given area. This is also why I think it is important to tune closed reed calls. It gives them a little different sound from other calls using the same reed. Remember a coyote is a dog, their hearing and sense of smell is what feed them and keep them safe. A coyotes hearing is unbelievable. and they, like dogs have a much better ability to locate and differentiate sounds. The only way to call predators in is to either find a dumb one or to outsmart a smart one. In order to do this you need to do things just different enough from other hunters to not alert the predator. Just talk to someone that has been hunting predators since before it was popular. Dollars to doughnuts they will tell you about the "Good old days" when they called animals in every stand. While this may be an exaggeration to a certain extent, I will guarantee you they did call more critters in.
These are just a few of my thoughts on this subject, I hope they help you. I could go on but I don't want to bore anyone. Again, I am not an expert on any aspect of calling predators, but I do spend alot of time doing it and I have a fair amount of success IN MY AREA. This is different than where you are, so I can not speculate about what the predators will do there. I wish I had the opportunity to hunt a more diverse area/habitat but it is just not feasible at this time.
Again, I hope this helps.