Deciphering a loon’s yodel
The peaceful song of the Common Loon is a reliable sign of its willingness to fight
Published: June 22, 2012
 Common Loon
The calls are part of a varied, highly expressive repertoire of sounds routinely made by the black and white waterbird. The others are the soft, simple contact call known as a Hoot; the long, haunting Wail; and the familiar Tremolo, which sounds like laughter but is in fact a distress call.
Yodels are the only vocalization made by the male alone, and they’re typically loud, capable of carrying up to almost 10 miles (16 km). They consist of a three-note introductory phrase followed by a series of two-syllable repeat phrases. Scientists say that yodels are primarily a territorial signal.
Males give the call immediately after arriving in the spring, and they repeat it, most often while crouching and turning from side to side, projecting the sound across a wide area, when a rival flies over their territory, lands on it, approaches within 65 feet (20 m), or actually attacks.
Researchers John N. Mager III, Charles Walcott, and Walter H. Piper observed the birds between April and July from 2002 to 2007. They discovered that the number of repeated phrases indicates the loon’s motivation to fight:
The larger the number, the greater the probability that territorial interactions will escalate to violence.
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