For most species, we have included audio recordings, spectrograms, and written descriptions of their flight call or flight calls. Although listening to the audio recordings will likely be the most useful means of learning a flight call, it is our hope that the spectrograms and flight call descriptions (and for some species, spectrographic descriptions) will help facilitate learning the flight calls by highlighting key differences between similar species. 

        For species which have one specific flight call, we typically only include that one call type on the guide, even though other vocalizations may occasionally be given in flight. For species that do not have one specific flight call (most blackbirds, for example), we include a variety of call types that are given regularly in flight. In some species we do not know of any flight call but provide examples of a call type that, for one reason or another, we believe may occasionally be used as a flight call.

        In some cases, when we have heard or recorded song or song fragments from nocturnal migrants, we indicate so in the species accounts. We do this mostly with species for which there is no known flight call. Almost any species may occasionally sing in nocturnal migration and we have not attempted to make note of every species we have heard doing so.

        For each species, we have attempted to present the most typical examples of their flight calls along with the more common variations. We realize that all species will exhibit variation beyond what we have presented. In some cases, no doubt, we have omitted common flight call variations and we encourage listeners to bring these omissions to our attention so that future editions of this guide may be more complete.

        Each species has a home page with two or more of the following sections:

Flight call description A brief description of how the flight call sounds along with a phonetic representation indicated by quotation marks. Although frequently awkward and certainly of limited value, we hope these descriptions will steer the listener to characteristics of the sound that they might not have otherwise noticed. In our flight call descriptions, we have attempted to limit our vocabulary to a few specific terms with specific meanings that we have defined in the glossary. We strongly recommend looking over the glossary before reading the descriptions in the species accounts in order to get a fuller sense of each term. We would also like to point out that all relative terms used in the descriptions should be taken in reference to the most similar group of species. For example, we refer to Chestnut-sided Warbler's call as relatively low-pitched. This should be taken in reference to other warblers, but not necessarily in reference to all other bird calls on the guide.

Spectrogram(s) Here we have chosen what, in our experience, is a typical example of the flight call or flight calls of the species for spectrographic representation. These are short cuts to give brief examples of the flight call(s). The spectrograms are directly linked to audio recordings, so that clicking the mouse on the spectrogram initiates playback of the sound. The associated audio recording is longer than the actual sound represented in the spectrogram. All examples, unless otherwise noted, are from diurnal recordings where the species was visually identified. Also, all spectrographic examples are from different individual birds unless noted. See spectrograms for more information on what a spectrogram is and how and with what parameters we made them.

Examples Here we include links to additional audio and spectrographic examples, some of which may represent less typical variations. In some cases these links are included on the species' home page below the Examples heading. In many cases there are links to separate pages that contain additional sounds and/or spectrogram examples. These will typically be under the heading of Diurnal and/or Nocturnal referring to the phase of day when the recordings were made. Unless otherwise noted, all spectrograms and audio in this guide are from visually identified birds during the day. Also, all cuts in the Examples section are from different individual birds unless noted.

Similar species Here we mention which species have similar-sounding flight calls and discuss their audible differences. In some cases, we provide links to comparison pages for similar sounding calls such as thrush-like calls, short rising "seeps", blackbirds, etc. The purpose of these comparison pages is to allow quicker comparison of the most similar calls. Note that we do not attempt to draw comparisons with species found outside the region covered by this guide. For example, in the Rose-breasted Grosbeak account, we do not discuss the very similar Black-headed Grosbeak, which is found primarily in the west.

Behavior Here we include a brief account of the species' migratory behavior (e.g., whether a diurnal or nocturnal migrant) and calling behavior. The purpose of this section is to help the reader know under what circumstances a given species is likely to use its flight call.

Subspecies For a few select species with two or more vocally distinct subspecies, we describe the subspecies' flight calls. We have not made a systematic effort to obtain recordings of all subspecies but instead have only included some of the more distinctive ones. However, we have included recordings from as broad a geographic area as possible in an attempt to cover geographic variation in flight calls.

Spectrographic description For certain similar species we have included spectrographic descriptions intended to summarize the basic characteristics of a species' flight call that are visible or measurable in the spectrograms. For more detail, see spectrograms.

Discussion Additional comments are included in this section for some species.

Audio playback

         This guide is intended to be used on personal computers equipped with speakers for audio playback or which have a soundcard so that headphones may be connected for listening. The quality of the recordings on this CD-ROM will be greatly affected by the quality of the playback system. If one has poor quality speakers on his or her computer, a solution is to buy a set of headphones and connect them to the speaker out or headphone out jack on their computer. Cheap headphones will reproduce sound much better than cheap computer speakers, and high-quality headphones will reproduce sound the best. Another option would be to invest in better quality computer speakers, or better yet, hook up your home stereo system to your computer's sound out jack.