The simple trilled songs of species like Chipping Sparrow and Dark-eyed Junco offer some of the most difficult, and most common, identification challenges in bird song. There is simply very little information that we can glean from the songs to help us identify the singer. Each species sings a rapid series of very short phrases on a steady pitch, with almost nonexistent pauses between each phrase, and in our brain the sound runs together to form a continuous trill.
Birds can hear a lot “faster” than we can, however, and consequently can extract a lot more information from the very rapid series of notes. The differences are there, and a Chipping Sparrow does not get confused by the songs of Pine Warblers or Dark-eyed Juncos. The key for the birder trying to identify these songs is to practice hearing the finer details. In most cases we can’t really hear the details of the individual notes, but we can hear the resulting “gestalt” differences in the overall tonal quality of the sound.
Listen for those differences in quality, as well as upslurs and downslurs, the overall length of the song, changes in volume, and differences between songs within a singing bout.
The trill of Chipping Sparrow is nearly twice as long as that of any other species, and this is a consistent and very useful clue. In addition, the overall quality of the sound is usually mechanical and rattling, due to the complexity of each individual phrase.
This recording includes two different song types alternating from one individual bird. The first song is slow, the second fast. This alternating pattern is common in Pine Warbler and is a good identification clue, as the other species sing only one song type and do not alternate.
The songs of Pine Warbler have the most gentle and musical-sounding overall quality of the group. This is a result of relatively simple whistled phrases, with less dramatic changes in pitch and less complexity. In the slower song here a clear upslur can be heard, as the ending of each phrase is distinctly higher-pitched than the beginning. No other species in this group commonly uses phrases that sound upslurred (Chipping Sparrow is just too fast and noisy to hear the pitch change), and that, combined with the musical whistled quality of the song, will allow you to identify most Pine Warblers with confidence.
These recordings are of two different song types from one individual bird. Each male has a repertoire of several different song types, but usually sings each one at least twenty times before switching to another, never alternating song types as Pine Warbler often does.
The songs of juncos are often described as “loose” and “jingling”. They lack the relentlessly mechanical sound of the Chipping Sparrow. The relatively slow overall tempo and narrow range of pitch produces a more musical sound, but the complexity of each phrase does lend a mechanical element, which leads to the overall description of the song as a “musical rattle” and gives it its jingling quality.
Compared to Pine Warbler notice that each phrase is descending in pitch. Listen to these recordings and compare to the Pine Warber above to practice hearing the difference in inflection. In addition, because of the very strong and clear notes incorporated into each phrase by the junco (especially in the slower song) the junco has a sharp “k” sound to the notes, as opposed to the softer “p” sounds of the Pine Warbler.
The song increases in volume, starting softly and “swelling” to a much louder and stronger sound, unlike any of the other species in this group. This is a fast trill, with a very sharp staccato quality to the notes because each one covers a wide range of pitch, downslurred then upslurred, in a very short time. The quality of the notes is high and sibilant (almost hissing), not rattling or jingling. The combination of sharp staccato quality and swelling volume is distinctive.
For comparison, a Pine Warbler is singing in the background, first heard at 0:13 seconds
There is no getting around the fact that these four species have very similar songs, and require a keen ear and a lot of care to identify. But by focusing on the differences described above, you should be able to identify most of the trilled songs you hear, and with practice your confidence will steadily increase.