The authors just fixed a bug affecting offline use of the app and now (Aug. 20, 2018) it works quickly and well. One can search by bird name, bird taxonomic group, hotspot and region. There are bird calls, lots of good pictures and even a bird ID quiz. The range maps are great, too. If you bird with an iPad/iPhone or an Android device, this is the Viet Nam birding guide for you. Nearby countries are covered by the app as well.