I have said many times that one of the great things about birdwatching is that there is always something to learn at all levels.

A beginner, of course, has a lot to learn as the world of birds is vast. An intermediate-level birdwatcher has a lot of knowledge, but there is still plenty more to learn, such as hybrid species and plumage phases. Even experts have a lot to learn as it is impossible to know everything about every bird in the world, and there are species and discoveries yet to be made.

Over the last few weeks, I have been writing a lot about warblers and other spring songbird migrants such as tanagers and grosbeaks. In my opinion, those types of birds straddle the line between beginner and intermediate-level birdwatching. There are a lot of nuances in that statement, however. Identifying warblers by sound is clearly a more intermediate or even advanced intermediate skill. But identifying a rose-breasted grosbeak at a feeder is more of a beginner skill.

There are many other types of spring migrants passing through or settling now in New England that fall clearly into the intermediate, or even expert, category. Vireos and flycatchers, I believe, are two types of birds that can be tricky to learn and therefore require a higher level of skill to identify. Both types of birds tend to favor the tops of trees and are difficult to get a good look at. Often, the sun is either hiding behind clouds or in your face, which makes identifying a bird even more difficult as the colors are not showing well through the binoculars.

A few of the vireos can be relatively easy to identify if you get a good, close look. The blue-headed vireo, with its obvious white spectacles, is one example. The red-eyed vireo is another example, but it is pretty rare that you get a good enough look to determine eye color. Similarly, great-crested flycatchers, with their relatively large bodies and boisterous songs and calls, can be another fairly easy identification.

But most vireos and flycatchers are largely brown or gray with subtle markings, making identification difficult for even intermediate birdwatchers. That is when learning their song and calls becomes important. But that, of course, is a more advanced skill, particularly when one is already trying to learn the song of warblers and other more common birds, such as Baltimore oriole and rose-breasted grosbeak.

In my opinion, vireos and flycatchers are often overlooked, or even ignored, by many birdwatchers. I myself am guilty of this as I rarely write about them in my column. The other day, however, I was struck by the beauty of a red-eyed vireo. I had a rare, extremely close look at the bird. I was walking through a small conservation area where bird banding was taking place, and the vireo was tangled in one of the mesh nets. I took a quick photo with my iPhone and rushed to alert one of the banders of the catch.

That sighting got me thinking about the other vireos and other birds such as flycatchers that are flitting among the treetops with little fanfare.

Several years ago, I brought my boys to a bird-banding area, and one of the banders allowed us to participate in the release of the birds. After all the pertinent information about the bird was collected, Andrew got to release a gray catbird, and Will, who was about 5 years old at the time, released a yellow-bellied flycatcher.

The vireo sighting the other day made me recall the release of the yellow-bellied flycatcher. Rarely on a bird walk are those birds found, and rarely are they discussed when the topic of New England bird comes up. But they are out there and count just as much as the warblers and other ballyhooed birds of New England.

Birdwatching can be a fairly easy hobby. If you are content to know a few common backyard birds such as robins, mourning doves, blue jays and cardinals, that is pretty easy to pick up. If that is your end goal in birding, that’s perfectly fine. If you desire to learn more and take the hobby to another level, that can be done, too, as birdwatching can be as difficult as you want to make it. I look at birds like vireos and flycatchers as birds that definitely take a birder to another level.