Cool app but I prefer the old-fashioned way with looking birds up in a paper book. Most of the time I don't even like having a phone with me. The experience in nature is better without it for me.
Paper books fall out of date, though. I ran into that problem with the Common Gallinule, which my old copy of Sibley called the Common Moorhen. It's not just name changes; species are merged or split fairly often, especially with DNA evidence coming in.
Once you figure out which species it is in the book, you can confirm it on the website once you get home with eBird. In my birding travels I've encountered about three cases where this has happened, and in all cases it's trivial to figure out what happened with eBird. I've seen over 700 species of birds btw in five countries and three continents and I've never had a problem with using a relatively recent book.
