One of the joys of spring is hearing the beautiful songs of returning migrant birds. Avian voices are works of art that can help us know what's around and lead us to the species we most want to see.

Learning bird songs, however, is not always easy. The typical translations we find in field guides, like the Yellow-throated Vireo'srrreeyoo, rreeoooee, are rarely useful in helping us identify songs. An easier way is to use "pictures of songs," called audio spectrograms, which help us see the underlying structures and qualities of a species' calling card and come up with a more objective ID. In this article, we'll explore five pairs of similar-sounding songs you might encounter in the yard or park, and use spectrograms to help us remember how to tease them apart. But first, a quick rundown of terms used:

Elements are single sounds—either single pitches or one smooth, continuous change of pitch.

Phrasesare collections of elements that repeat as a group. For example, the Carolina Wren'stea-kett-le, tea-kett-le, tea-kett-le is a series of three-element phrases.

Sectionsare groups of similar elements and phrases that may be marked by a change in pitch, speed, or phrase type.Dah, dah, dah, dah, dah, uh ooh, uh ooh, uh ooh is a two-section song.

Transliterations are our attempts to translate songs into vowels and consonants. They sometimes work, but often only for the person who made them.

Song clips belong to the Audubon North American Birds Guide and app and were recorded by Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others. Spectrograms were created by Tom Stephenson using the BirdGenie app.

American Robin vs. Rose-breasted Grosbeak

American Robins are prolific singers that can be found in a wide range of habitats, from forests to fresh-cut lawns. But in Eastern springs they can be confused with Rose-breasted Grosbeaks, which descend on shared wooded habitats. Thankfully, there are two main differences in the two species' voices.

American Robin:

Rose-breasted Grosbeak:

American Robin phrases are made up of elements with very fast pitch changes. This gives their songs a "wobbly" characteristic. Rose-breasted Grosbeak phrases also have pitch changes, but they are slower, smoother, and more evenly slurred in between.

What's more, American Robin phrases follow a regular rhythm. The grosbeak's phrases alternate between regular rhythms and irregularly placed phrases, making their songs a conductor's worst nightmare.

Common Yellowthroat vs. Carolina Wren

From left: Common Yellowthroat. Photo: Boe Baty/Audubon Photography Awards; Carolina Wren. Photo: Mike Smeets/Great Backyard Bird Count

Common Yellowthroats and Carolina Wrens can often be heard in spring and summer in scrubby fields, bottomlands, and forest-edge habitat in the Eastern United States. Both species' songs have the same structure: one section, usually consisting of the repetition of a three-element phrase. The warbler's mnemonic is wit-chi-tah, wit-chi-tah, wit-chi-tah, and the wren's is tea-kett-le, tea-kett-le, tea-kett-le. But since one person's witchitah can be another person's teakettle, we need a better way of separating the two sounds.

Common Yellowthroat:

Carolina Wren:

The Common Yellowthroat's song consists of slow slurs with shallow pitch changes. The Carolina Wren's song, on the other hand, contains one abrupt, accented element, giving it a strong, repeated accent that stands out from the warbler's even and smooth performance. Listen carefully for that accented element and you'll find these species less confusing in future springs.

Bullock's Oriole vs. Hooded Oriole

From left: Hooded Oriole. Photo: Virginia Short/Audubon Photography Awards; Bullock's Oriole. Photo: Rick Derevan/Audubon Photography Awards

The range of the Bullock's Oriole is much larger than that of the Hooded Oriole, but they share much of the same breeding territory across California, Arizona, New Mexico, and Texas. Both species' songs consist of a variety of whistles, chatter, scolding, and other raucous notes. With all of that cacophony, you can't be sure which oriole is which.

Bullock's Oriole song:

Hooded Oriole song:

To suss out the two species, let's look at the rhythmic arrangement of their songs. It's also useful to take an "inventory" of how many different kinds of buzzes, trills, scolds, and slurs each species uses. This approach of noting the number of phrase types can be helpful when identifying other species, too.

Bullock's songs are somewhat consistent in their form: They usually start with a rhythmic repetition of harsh calls, move into a short section of clear slurs, and end with another section of repeated phrases (often trills). Hooded Orioles have a more ecelectic style with seemingly random, fast changes between slurs, harsh notes, and imitated calls. Subsequent songs for the species can vary in form and phrase content. Bullock's songs tend to remain similar throughout the session.

The orioles' calls, which are almost always woven into their songs, prove revealing, too. Each species has at least two types: one a harsh chatter and the other a slur. The harsh calls are similar, but the Hooded's is higher, faster, and often doubled. The Hooded's slur is also higher and rising, while the Bullock's slur is rich and descending.

Bullock's Oriole call:

Hooded Oriole call:

American Goldfinch vs. Lesser Goldfinch

From left: American Goldfinch. Photo: Megumi Aita/Audubon Photography Awards; Lesser Goldfinch. Photo: Lou Orr/Great Backyard Bird Count

The American Goldfinch shares much of its sprawling Western territory of fields, scrub, feeders, and edge habitats with the Lesser Goldfinch. Females of the two species can be especially tough to identify.

As we found with the orioles, structural arrangement and interspersed call notes are key for teasing the songs apart.

American Goldfinch song:

Lesser Goldfinch song:

American Goldfinch songs include a ton of recycled phrases. Lesser songs also have repetitive parts, but they also wrap in single notes picked up from other species' calls. This looser structure leads to a wider range of phrases and more "jumbled" song quality.

Call-wise, both species embed calls within their songs. The American Goldfinch has a short, clear, falling call that's usually repeated in fast sequence. It also has a rising call that's more drawn out and complex.

The Lesser Goldfinch's rising call is simpler, shorter, and less complex.Likewise, its falling call is a much slower slur than the American's. In addition to those two option, it has a simple, harsh chet that might repeat.

American Goldfinch call:

Lesser Goldfinch call:

Song Sparrow vs. Bewick's Wren

From left: Bewick's Wren. Photo: Susan Holtz/Audubon Photography Awards; Song Sparrow. Photo: Christine Haines/Great Backyard Bird Count

Song Sparrows are master vocalists: A single male can have a repertoire of more than 10 song types. This is true across their range, which extends over much of the United States and Canada. Their musical counterparts, the once common Bewick's Wren, overlap with them across the Western and Central United States. The songs of both species include trills, buzzes, and clear notes—but their call notes are distinct.

Song Sparrow:

Bewick's Wren:

Song Sparrows usually start their songs with a pair of terse elements, separated by a jump in pitch. They have several different calls as well, but rarely include them in their songs.

Bewick's Wrens, on the other hand, kick off their songs with a harsh, rising zweep call. Their notes are generally higher, thinner, and more nasal than the sparrow's and incorporate harsh, rising buzzes. Song Sparrows buzz, too, but often at lower, steady pitches.

Overall, the wren's song looks a lot simpler than the sparrow's with one-element phrases compared to two or three.

One last clue: Check out the end of the spectrograms above. Both species tend to use rapid-fire elements in their encore—the Bewick's a slow to fast trill and the Song Sparrow a characteristic buzz.