Which bird app?

Most identification apps start by asking you to take a picture. Feather Trove starts from the opposite end: it scans the photo library already on your iPhone, works out which images probably contain a bird, and hands you a queue to review.

That is a genuinely different task. If you have years of holiday photos with a heron in them somewhere, this is the app that finds the heron. Identification runs on the device. The suggestions are a starting point — you confirm or reject each one, and what survives becomes a life list with dates and places attached.

Cornell Lab's app is free, and for a bird you can hear it has no real competition. Hold up the phone and Sound ID puts names against the song as it happens, which is the closest thing birding has to a magic trick.

Photo ID works too, one image at a time, and the whole thing runs offline once you have downloaded a regional pack. The workflow assumes you are outdoors and curious. Point it at a camera roll of two thousand photos and it will politely ask you which one you meant.

eBird is not an identification app and does not pretend to be. It is a notebook with a database behind it: species, counts, location and time, submitted to an archive that researchers and conservationists actually use.

If you have ever come home from a good morning and wished you had written it down properly, this is the fix. Checklists work offline and sync later. Pair it with one of the two apps above when you need help with a name.