What are crossbills? Crossbills are seed-eating finches of mountains and conifer forests, known for their unique lifestyle. They are nomads, and search over broad areas for ripened conifer cones. Their unusual, crossed bill allows them to rip and tear between cone scales to extract seeds.

What is the crossbill problem? A number of distinctive kinds of crossbills are currently lumped as one species, the "red crossbill", under the scientific name Loxia curvirostra. However, recent analysis indicates that these distinctive red crossbill forms are full species. A major problem is that the different species of red crossbill are difficult to distinguish from each other. Differences in size and coloration are slight. Fortunately, it is now known that diagnostic differences in vocalizations occur among the various forms.

The purpose of this web site is to help professional and amateur ornithologists compare acoustic differences among North American red crossbills.

These pages enriched with audio files in AIFF format. To access the audio, Netscape 2.0 or higher is required, and it must be equipped with the LiveAudio plug-in (standard with N'scape 3.0). To test your browser, try these examples by 1) clicking the play button, or 2) clicking the call note sonogram to download the audio to an external viewer:

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To go to other parts of this guide, link to the Crossbill Audiovisual Guide Directory.

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This Web site is part of a growing collection of information provided by the Department of Ornithology of the research facilities at the American Museum of Natural History. See my home page for other links.