hello. welcome to expert village. my nameis wayne petersen and i'm the director of the important bird areas program for the massachusettsaudubon society. today, we're here at the daniel webster wildlife sanctuary in marshfield.and, we're going to be talking about birding by ear. another of our really beautiful songbirds is the hermit thrush. its song, by all accounts, is one of the most spectacular innorth america. one of the interesting things that people who study bird songs do is torecord the songs and then electronically look at registrations on what are called sonograms.and when one looks at the sonogram of a bird like the hermit thrush, we find that thereare some registrations that are very heavy and rich and others that are very fine andthen that almost go up into the inaudible
range for human hearing. so that, in additionto the fact that hermit thrushes, like the wood thrush that we mentioned earlier, sohave the ability to literally produce two sounds at the same time with their syrinx,as opposed to our larynx. there are also sounds withing the song that probably unless we sortof slow them down electronically, we hardly hear at all. our hearing is just not sensitiveenough to pick up some of the nuances that are incorporated into the hermit thrush'ssong. but, undoubtedly to the hermit thrush, from one to another individual, they're ableto pick up all of these variations. and, this is one of the ways that hermit thrushes sortof recognize the fact that if you're a female hermit thrush, this is my mate, not the mateof the territorial bird next door.