Seek by iNaturalist — the scientific reference
Free, no account, backed by the largest citizen-observation database in the world. Seek identifies live in the viewfinder and covers plants, fungi and animals. Its limit is also its strength: it is cautious, and prefers returning a genus or family over a species it doubts.
iNaturalist — peer validation
Heavier, aimed at scientific recording. A posted observation is verified by the community, which gives the best reliability on the market — at the cost of a delay measured in hours or days, and an interface built for naturalists.
Picture Insect — the specialist
Excellent on insects and spiders, precisely because it does nothing else. A specialised model often beats generalists on its home ground. The subscription arrives quickly, though, and outside arthropods it has nothing to say.
Merlin Bird ID — the best on birds
Free, built by the Cornell Lab of Ornithology. Merlin identifies by song as well as by photo, which is decisive for birds: you hear them far more often than you see them. If you only do birds, it is the obvious choice.
SafaRoll — identification that leaves something behind
One model across the whole animal kingdom, an answer in about a second, and above all an object at the end: the photo becomes a collectible card, with its rarity and its painted scene. The bet is simple — an encyclopedia entry is read and forgotten, a collection fills up and makes you want to go back out.
Summary
- Birds only, song included: Merlin.
- Validated scientific recording: iNaturalist.
- Insects and spiders: Picture Insect.
- All life, free, cautious: Seek.
- The whole animal kingdom, with a collection to fill: SafaRoll.