| Song Phrase 1 | Song Phrase 2 | Song Phrase 3 | Male Position Note | Female Position Note |
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Usage: Male Advertising Song (MAS), of which this phrase is a part, is used primarily for mate attraction
(Ainsley 1992). Structure: Click "Song Phrase 1" above and below to compare the two species. This very simple, high, brief note is rather variable within species, and consistent geographic differences in its shape have not been documented. As the red lines on the spectrograms show, it is consistently above 6 kHz in PSFL and below 6 kHz in COFL. This note and FPN are distinctly different in frequency (pitch) and spectrographic shape. Nevertheless, as indicated by the similarity of the transliterations authors have used to evoke Song Phrase 1 and FPN, the two will be exceedingly hard to distinguish in the field unless you have perfect pitch. They do, however, appear in entirely different contexts. |
Usage: Male Advertising Song (MAS), of which this phrase is a part, is used primarily for mate attraction
(Ainsley 1992). Structure: Click "Song Phrase 2" above and below to compare the two species. Song Phrase 2 is the single most dramatic difference between COFL and PSFL. The barely audible "tick" note at the beginning is below 3 kHz in COFL and above 4 kHz in PSFL, a difference of more than 1000 Hz. This little note, which is also present in Song Phrase 3, gives an easy assay of the overall pitch of the song. The highest frequency of this phrase is also typically more than 1000 Hz lower in COFL. The peak is typically at or just above 6 kHz in COFL, and from 7 kHz to over 8 kHz in PSFL. There is also a difference in shape. The peak frequency is at the apex of a sharp point in PSFL, while the apex is rounded in COFL. In the classic COFL version, this note then descends abpruptly in frequency, then levels off. In PSFL there is a break, and two notes are produced instead of the continuous single note of COFL. The lowest frequency in this region remains higher than the top of the "tick" in COFL, while it is lower in PSFL. Typically, there is a dip (a concavity) in this final note of PSFL, while the corresponding part of the COFL phrase is convex upward or flat. COFL Phrase 2 exhibits a lot of variation, even in the core range of this species. In extreme cases, it broken into two notes (in addition to the "tick"). An example of this version is the fifth (rightmost) sound in COFL Phrase 2 above. This variant has been recorded in NM and UT. It is also found commonly in the Warner Mountains of south-central Oregon and northeastern California. Song phrase 2 is sometimes used like a position note, i.e., not in sequence with the other two song phrases. This may lead to confusion, especially when it is alternated with the real position note. If "continuous" position note means PSFL and a "broken" position note means COFL, as it seems to for many observers, then clearly interpreting Song Phrase 2 as a position note can lead to error. If both the MPN and Song Phrase 2 are given in a leisurely fashion, without the other two song phrases, it may lead to the impression of "bilinguality." For a comparison of the transliterations authors have used to evoke Song Phrase 1, click here. |
Usage: Male Advertising Song (MAS), of which this phrase is a part, is used primarily for mate attraction
(Ainsley 1992). Structure: Click "Song Phrase 3" above and below to compare the two species. Song Phrase 3 is the easiest phrase to compare. COFL and PSFL have the same three notes, although all three are more than 1000 Hz higher in the latter. The initial "tick" is below 3 kHz in COFL and above 4 kHz in PSFL, as is the case in Song Phrase 2. The main difference, though, is emphasis. COFL typically emphasizes the middle note, which is usually highest (but see the variation above). PSFL typically de-emphasizes this note, leaving the initial "tick" more audible than in COFL. Usually the middle note of PSFL is neither visible on a spectrogram nor audible. The contrasting Low-High sequence of PSFL and High-Low sequence of COFL was Johnson's favorite field character for distinguishing coastal from interior birds. As you see, the two emphasized notes of COFL Song Phrase 3 do not differ much in pitch, so "High-Low" may be a stretch. But, there is no denying the consistent difference in emphasis in the two species. For a comparison of the transliterations authors have used to evoke Song Phrase 3, click here. |
Usage: Used primarily in territorial defense. Also upon approaching nest. Finally, accompanies flights during
Male Advertising Song (MAS)
(Ainsley 1992). Structure: Click one of the numbered links for "Male Position Note" above and below to compare the two species. There are two panels for COFL and three for PSFL. Note that most COFL MPNs start below 4 kHz and end below 6 kHz, while PSFL MPNs typically start at or above 4 kHz and sweep past 6 kHz at the end. The Male Position Note is the most frequently heard sound of these species, and birders have focused on it as a diagnostic character. The classic criterion is that the PSFL MPN is continuous, while the COFL version is discontinuous. As the last two examples for COFL show, not all birds in the core range of COFL give two-parted calls. Moreover, continously rising sounds have been recorded in Colorado. Although these may not be MPNs, technically, that doesn't keep them from contributing to confusion. PSFL MPNs also vary considerably, especially in the Pacific Northwest. Females of PSFL, and probably COFL, may use the MPN to duet with their mates while incubating (Davis et al. 1963), and the faithfulness of female MPNs to the male standard for the two species is not known. Then there is the problem of bilinguality. Consequently, I recommend not identifying a member of the Western Flycatcher Complex to species on the basis of MPN alone. Even a Female Position Note will help with an identification, because of the 1000-Hz higher pitch of the PSFL. What you really need, though, is Song Phrase 2 and Song Phrase 3, and that means going out before dawn. See the field notes that accompany the List of Geographic Samples for information on the time of day when song is most likely to be heard. For a comparison of the transliterations authors have used to evoke the Male Position Note, click here. |
Usage: On breeding territory, used primarily by female near nest in exchanges with mate
(Ainsley 1992).On migration and wintering grounds thought to be used by both sexes.
Used by both sexes in alarm (N. K. Johnson in Buckely and Mitra (2003)). Structure: Click the link for "Female Position Note" above and below to compare the two species. The "shape" of the FPN of the Western Flycatcher Complex is unique in Empidonax; it is a downward-pointing chevron. (The "pip" notes of Hammond's Flycatcher and Alder Flycatcher are upward-pointing chevrons.) The tip of this chevron is typically above 7 kHz in PSFL and well below that level in COFL. On present knowledge, this shape should serve to distinguish FPN from the equally simple and very similar Song Phrase 1. |