I’ve been using anki flash cards to learn birds in my local area. It works really well, in a few weeks I could identify a few score different birds.

I’ve also used Anki to learn some plants and insects.

Also, if you Reddit, subscribe to r/whatisthisbird (along with whatisthisbug and r/birding), and every day you’ll learn birds and bugs. I also do this with artwork as my random desktop background. I see it every day, so I can now recognize some paintings. I put no effort into learning, they’re just there and I pick it up passively! Should work with pics of birds.