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Spectrograph Library


Nocturnal flight calls of small passerines in eastern North America


Below are typical spectrograms of various species' night flight calls that may be detected by audio stations in eastern North America.  Some species' calls are spectrographically distinctive; others are very similar to one another and are lumped in similar species categories. The calls displayed are all in the 6-10 kHz frequency range and typically less than 150 mS in duration. Such calls may be automatically detected from tape recordings or directly from a microphone using the detection programs Tseep (see analysis software).  All these spectrograms were made with a 512 FFT, Hanning window, a frame length of 11.6 mS, and a frame overlap of 87.5% (hop size of 12.5).  The Black-and-white Warbler call was made with frame length of 2.9 mS to better illustrate the call's frequency modulation.  To duplicate this resolution on your call datasets using the spectrogram viewer Glassofire, open Glassofire and go to the spectrogram selection on the menu bar, select the options section, and then select parameters and fill in the values above in the correct locations.  The library below is a very basic representation.  Stay tuned for additional examples illustrating species variation and additional species categories. Also note the Flight Call Guide, which has many additional examples and provides the basis for the species identification of these calls.



American Redstart



Black-and-white Warbler



Bay-breasted Warbler



Black-throated Blue Warbler



Canada Warbler



Chestnut-sided Warbler



Cape May Warbler



Common Yellowthroat



Grasshopper Sparrow



Henslow's Sparrow



Hooded Warbler



Indigo Bunting



Northern Waterthrush






Savannah Sparrow



Wilson's Warbler



"Zeep" complex

Connecticut Warbler; Blackpoll Warbler; Yellow Warbler; Cerulean Warbler; Blackburnian Warbler; Worn-eating Warbler; Magnolia Warbler; Louisiana Waterthrush;



Double-banded upsweeps

Tennessee Warbler; Nashville Warbler; Black-throated Green Warbler; Orange-crowned Warbler; Mourning Warbler; Yellow-rumped Warbler; Vesper Sparrow; White-crowned Sparrow



Single-banded upsweeps

White-crowned Sparrow; Golden-winged Warbler; Blue-winged Warbler; Yellow-rumped Warbler; Prothonotary Warbler; Swainson's Warbler; Clay-colored Sparrow



Single-banded downsweeps

Parula Warbler; Pine Warbler; Field Sparrow; Bachman's Sparrow?



Double-banded downsweeps

LeConte's Sparrow; Nelson's Sharp-tailed Sparrow; Seaside Sharp-tailed Sparrow; Savannah Sparrow



Lincoln's/Swamp Sparrow complex


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