Yesterday, while hiking around Cat Lake near Isabella I encountered 3 singing black-throated blue warblers. Two were exclusively whisper singing; the third did it briefly. Unlike the robin's whisper song, these birds were singing a song identical in all respects to one of their typical songs, except for volume. At a little over 100 feet distance from the birds I could only faintly hear them. I'm curious if others have heard black-throated blue warblers doing this.
Steve Wilson ---- Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net Archives: http://lists.umn.edu/archives/mou-net.html