Even with birds whose songs you have just learned, listening a time or two may not be enough to give you confidence when trying to identify them by ear in the field. And remember, most of these have an expansive "bird vocabulary"; each may have alternate songs and a number of calls used for different purposes (contact calls, mating calls, alarm calls, mobbing calls, etc.) So there is A LOT more to learn about just these first twelve birds. Here are a few suggestions.
Practice with the basic calls/songs of this first set of birds.
Listen to the recordings, then go out and try to hear them in the field. Try listening early in the morning during spring for what's known as the "dawn chorus". Do you hear songs you recognize? Do you know which bird is making that sound?
Consider practicing identification of these bird songs using apps designed for the purpose such as "Larkwire". This app can turn learning bird sounds into a game and can be set up to play with just the birds we've started with by creating a playlist. Then you can add more species as your skill and interest grow. The app is free but you'll need to purchase a "song pack". I suggest starting with at least the "Birder Pro" pack which includes the land birds of eastern/central North America, and you can certainly upgrade to include the whole continent and add the water birds too.
Just as we observe details beyond color when we look at a bird (eye rings and other facial markings, wing bars, shape and size of bill, etc.) you can learn to listen for and label details of bird songs. Is the sound at the same pitch or does the pitch go up or down? How about the pace; is it steady or does it increase or decrease? Is the pace too fast to count the notes/phrases or can you hear individual notes?
Learn to see birdsongs. Yes, see them. As Donald Kroodsma says, "nothing improves one's hearing more than being able to hear and see a sound simultaneously." Many of the references on the "Additional Resources" page of this site include a chart for the sounds, known as a spectrogram, which interprets the sound visually. Audubon has a good explanation here, and you may also wish to refer to the section on spectrograms at Earbirding.
Participate in Four Rivers Audubon's (or your local Audubon chapter's) birding outings. This is the VERY BEST way to learn more about birds! During outings listen, try to identify the birds you hear, and ASK QUESTIONS!
You're likely asking, "How about Merlin, Song Sleuth, and other bird sound ID apps?" They are great and you'll want to use them (links are provided on the "Additional Resources" page.) But while such apps are a fantastic aid to identity, they are not a magical solution because:
It can be a challenge to get a useable recording of birds, especially when multiple species are singing at once. The Hooded Warbler in the background which has you stumped may be drowned out by the Carolina Wren singing much closer.
Even when you get a good recording the apps themselves will tell you that they're only suggesting what the bird might be, not guaranteeing ID. It's still up to you to confirm the identification!
You'll definitely want to use such technology, and they really are very helpful so long as you keep the caveats in mind. These apps are an AID TO not a SUBSTITUTE FOR learning the songs and calls yourself.
There are of course way more than 12 birds vocalizing out there. Below is a list of some other species that you're almost certain to hear in our area during springtime, and there are plenty more still. When you're ready, study them just as you did in the first twelve on this site (and add them to your Larkwire playlist!) But when you've got confidence in identifying the 33 species listed on this site you'll be more skilled than most at birding at ear!
Use Cornell Lab of Ornithology's "All About Birds" (the bird names on the list below link to the bird's sound page there), search "xeno-canto" and/or other online guides, and add them to your Larkwire playlist as mentioned above in order to begin learning the sounds of these species:
There are some bird sounds which at first may sound very much alike. But you can learn to sort them out. Again, there are many more examples than what's listed on this site. While you should study each just like you have with the other species, this is where Larkwire really shines! You can easily play the pairs and test your skill at distinguishing them.
The Barred Owl and Great Horned Owl sound very different but can be confusing if you've not listened to them before.
We've all heard Northern Mockingbirds sing, but perhaps have sometimes confused it with the Brown Thrasher. Listen for the number of times the bird repeats a phrase; it's usually 2 or 3 repetitions with a Brown Thrasher and 3 or more for the Mockingbird.
For most of us, the only way we can distinguish American Crows from Fish Crows is by their calls. We have both so it's worth learning the differences (and the distinction in the call and its tone is easy to pick up.)
The Red-eyed Vireo and Yellow-throated Vireo sound very much alike. But listen to the difference in pace and tone and you'll be able to tell them apart. (Hint, a nickname for the Red-eyed Vireo is "Preacher Bird" because it never shuts up, just like this author during his time in the pulpit. And it's said the Yellow-throated Vireo sounds like it has a cold.)