Hello everyone. In my testing of the light versions or free versions of these apps. I find the adubon apps except one nature tap are accessible. Nature tap may be accessible I didn't play with it long. Audubon apps are made by green mountain digital In my findins I found audubon apps have much better labeled sounds that ibird does. And their organization in my opinion is much better designed. And works better with voice over than ibird. Ibird on the other hand has a bit more detail on each bird although if you want more detail you could use wikipedia. And it has a few more/different features than audubon apps do. So really it depends on your interests. I am going with audubon. I like how the sounds are labelled better there. And I like that they have apps for more than just birds. Mainly I am chosing audubon over ibird simply because i like the layout with using voice over better. But it is really a personal choice. Ibird has more birds in their app. But a lot of their birds may be a similar bird just named differently because it is from a different region or whatever. At least this has been my observation from what I have read. It really depends on what you want the app for and what your going to use it for. Me I like learning. So I am after the information. Other people may want to take photos or something. I think both developers support this in the different apps. But I also like sounds. audubon has 8 hous of bird sounds compared to ibird's 5. And like I said the sounds in audubon are labelled much better. Again this is all based on the free or light versions of these apps. People can share their thoughts of course. Each person may use what works for them. I however like audubon's content and layout and variety of things more than just birds more. They don't have hawaii. But who knows they may add it as another app down the road at some point. Again both ibird and audubon look great. I just like audubon better. Just thought I would share.