The Blue-headed Vireo (Vireo solitarius) and Red-eyed Vireo (Vireo olivaceus) are two similar looking songbirds found in North America. They can be tricky to tell apart by sight, but their songs are quite distinct. In this article, we’ll go over the key differences between Blue-headed Vireo and Red-eyed Vireo songs and calls to help birders identify these vireos by ear. We’ll cover song length, pace, pitch, frequency, and more. Being able to recognize the unique songs of these two vireos is an important identification skill for birders.
Blue-headed Vireo Song
The song of the Blue-headed Vireo is a simple, relaxed repetitive warbling. The song consists of short phrases that are repeated 3-6 times in a row. Each phrase lasts about 1-2 seconds, with a pause of 1-2 seconds between phrases. The phrases have an ascending slurring quality, going up slightly in pitch at the end of each phrase.
The song often sounds like “see you, see you, see you” or “cheer up, cheer up, cheer up.” It has a smooth, lazy, blurry quality compared to many other vireos. The tone is rich and bell-like. The Blue-headed Vireo song is slower paced compared to the Red-eyed Vireo. It has a lower pitch as well, with the song staying in the frequency range of 4-5kHz.
Red-eyed Vireo Song
The Red-eyed Vireo has a much more energetic, rapid, persistent song than the Blue-headed Vireo. The Red-eyed Vireo song consists of short, repetitive phrases delivered in rapid succession without pauses in between. Each phrase lasts about 0.5-1 seconds.
The Red-eyed Vireo song sounds like “here I am, where are you? I’m over here!” with a questioning, rising quality on each phrase. It sometimes sounds scolding or accusatory in tone. This song is faster paced and more repetitive than the Blue-headed Vireo’s song. The Red-eyed Vireo song also has a higher pitch, in the 5-6.5kHz frequency range.
Detailed Comparison
Pace
One of the most noticeable differences between Blue-headed and Red-eyed Vireo songs is the pace. The Blue-headed Vireo sings at a relaxed, slow, lazy pace with noticeable pauses between each phrase. The Red-eyed Vireo sings much faster, stringing together many phrases in rapid succession without pausing.
Pitch
The Blue-headed Vireo sings in a lower frequency range, around 4-5kHz. The Red-eyed Vireo sings higher, in the 5-6.5kHz range. The Red-eyed Vireo’s song has a more piercing, urgent quality due to the higher pitch.
Phrase Length
The Blue-headed Vireo’s phrases are longer, lasting about 1-2 seconds each. The Red-eyed Vireo’s phrases are very short, each less than 1 second long. This allows the Red-eyed Vireo to sing much faster.
Repetition
Both vireos repeat short phrases in a repetitive song, but the Red-eyed Vireo repeats its phrases many more times in succession without pausing. The Blue-headed Vireo repeats phrases less often (typically 3-6 times) with pauses between each repeat.
Song Complexity
The Red-eyed Vireo has a larger repertoire of phrase variations in its song and mixes up phrases more often. The Blue-headed Vireo repeats the same phrase in a more monotonous fashion. The Red-eyed Vireo song sounds more complex with greater variety.
Song Shape
The short phrases in the Blue-headed Vireo’s song have an ascending slurred or blurry quality, going up slightly in pitch at the end of each phrase. The Red-eyed Vireo’s phrases have a more questioning, rising inflection at the end.
Tone
The Blue-headed Vireo’s song has a rich, lazier, blurry tone compared to the sharper, scolding quality of the Red-eyed Vireo song. The Blue-headed Vireo sounds more lackadaisical and mellow.
| Feature | Blue-headed Vireo | Red-eyed Vireo |
|---|---|---|
| Pace | Slow, relaxed | Fast, rapid |
| Pitch | Lower, 4-5kHz | Higher, 5-6.5kHz |
| Phrase Length | 1-2 seconds | Under 1 second |
| Repetition | 3-6 repeats with pauses | Higher repetition without pauses |
| Complexity | Less complex, monotonous | More complex with variations |
| Shape | Ascending slur at end | Rising inflection |
| Tone | Rich, mellow, blurry | Sharper, scolding |
Other Differences
Habitat
Blue-headed Vireos prefer dense, mature deciduous and mixed forests, especially with tall trees. Red-eyed Vireos are more flexible, inhabiting both forest and open woodland habitats. Knowing the habitat can provide helpful clues when identifying these vireos by song alone.
Geographic Range
Blue-headed Vireos breed farther north than Red-eyed Vireos across Canada and the northeastern United States. Red-eyed Vireos have a more southerly breeding distribution extending into the southeastern states. The range difference means only Red-eyed Vireos breed across much of the southern U.S.
Migration Timing
The earlier spring arrival of Red-eyed Vireos compared to Blue-headed Vireos also aids identification in regions where they co-occur. Red-eyed Vireos arrive 3-4 weeks earlier on breeding grounds in the northeast.
Nesting
Blue-headed Vireos build pendulous, suspended nests on horizontal branches. Red-eyed Vireo nests are more conventional cups placed in a fork of branches. The differing nest structures are a useful clue for identification.
Visual Differences
While best identified by song, Blue-headed and Red-eyed Vireos do show some subtle visual differences:
- Blue-headed Vireos have blue-gray heads with a white spectacled eye-ring.
- Red-eyed Vireos have gray heads with no eye-ring and dark red irises.
- Blue-headed Vireos have yellow spectacles extending in front of the eye.
- Red-eyed Vireos lack yellow spectacles in front of the eye.
- Blue-headed Vireos have yellow flanks.
- Red-eyed Vireos lack yellow flanks.
Calls
The calls of these two vireos also differ. Blue-headed Vireo call notes include a sharp, rising “cheep” and a descending, buzzy “zeep.” Red-eyed Vireo call notes are shorter, higher-pitched clicks, chips, and whines. These call differences provide additional identification help.
Hybridization
Blue-headed and Red-eyed Vireos sometimes interbreed where their ranges overlap. The resulting hybrid songs can show intermediate features blending aspects of both species’ vocalizations. Hybrid songs may be more difficult to assign to one species or the other. Looking for multiple features is recommended when evaluating possible hybrids.
Conclusion
In summary, Blue-headed and Red-eyed Vireo songs differ significantly in pace, pitch, phrase length and shape, complexity, and overall tone. Red-eyed Vireos sing faster repetitive phrases with greater pitch variety at a higher frequency. Blue-headed Vireos sing slower, lower, more monotonous songs with an ascending blurry slur to each phrase. Remembering these key song differences, along with habitat, range, and visual characteristics, allows birders to confidently distinguish these often challenging species. Listening to both species takes practice, but their distinct musical voices become easier to identify over time. Careful aural study is the best way to learn the unique songs of the Blue-headed Vireo and Red-eyed Vireo.
