Editing Common loon (section)

===Vocalizations===

The common loon produces a variety of vocalizations, the most common of which are the tremolo, the yodel, the wail, and the hoot. Each of these calls communicates a distinct message. The frequency at which it vocalizes has been shown to vary based on time of day, weather, and season. It is most vocally active between mid-May and mid-June. The wail, yodel, and tremolo calls are sounded more frequently at night than during the day; calls have also been shown to occur more frequently in cold temperatures and when there is little to no rain.<ref name="Mennill2014" />

{{Listen|filename=Common loon tremolo.ogg|pos=right|title=Common loon tremolo call}}
The tremolo call—sometimes called the "laughing" call—is characterized by its short, wavering quality. It often uses this call to signal distress or alarm caused by territorial disputes or perceived threats.<ref name="Mennill2014">{{cite journal|last1=Mennill|first1=Daniel J.|date=2014|title=Variation in the vocal behavior of common loons (''Gavia immer''): Insights from landscape-level recordings|journal=Waterbirds|volume=37|issue=sp1|pages=26–36|doi=10.1675/063.037.sp105 | doi-access=free }}</ref> It emits a tremulous series of up to 10 rather high notes ''(hu)-heheheheheheha''.<ref name="hbw2"/> It also uses the tremolo to communicate its presence to other loons when they arrive at a lake, often when they are flying overhead. It is the only vocalization used in flight.<ref name="vtfishandwildlife">{{cite web|url=http://www.vtfishandwildlife.com/get_the_lead_out_looncall.cfm|title=Loon Vocalizations: What are you hearing and what does it mean?|publisher=Vermont Fish and Wildlife|archive-url=https://web.archive.org/web/20140913011626/http://www.vtfishandwildlife.com/get_the_lead_out_looncall.cfm|archive-date=13 September 2014|access-date=27 August 2017}}</ref> The tremolo call has varying three levels of intensities that correlate with a loon's level of distress, and the types are differentiated by increasingly higher pitch frequencies added to the call.<ref name="Barklow">{{cite journal|last1=Barklow|first1=William E.|year=1979|title=Graded frequency variations of the tremolo call of the common loon (''Gavia immer'')|journal=The Condor|volume=81|issue=1|pages=53–64| url=https://sora.unm.edu/sites/default/files/journals/condor/v081n01/p0053-p0064.pdf | doi=10.2307/1367857|jstor=1367857}}</ref>

{{Listen|filename=Loon yodel.ogg|pos=right|title=Male Common loon yodel call}}
The yodel is a long and complex call made only by the male. It is used in the establishment of territorial boundaries and in territorial confrontations, and the length of the call corresponds with the loon's level of aggression.<ref name="Mager2012">{{cite journal|last1=Mager III|first1=John N|last2=Walcott|first2=Charles|last3=Piper|first3=Walter H|date=2012|title=Male common loons signal greater aggressive motivation by lengthening territorial yodels|url=https://www.researchgate.net/publication/257920946 |journal=Wilson Journal of Ornithology|volume=124|issue=1|pages=73–80|doi=10.1676/11-024.1|s2cid=85216811}}</ref> The dominant frequencies in the yodel indicate the body mass and thereby the health of males.<ref>{{Cite journal|last1=Mager|first1=John N.|last2=Walcott|first2=Charles|last3=Piper|first3=Walter H.|title=Male common loons, ''Gavia immer'', communicate body mass and condition through dominant frequencies of territorial yodels |journal=Animal Behaviour|volume=73|issue=4|pages=683–690|doi=10.1016/j.anbehav.2006.10.009|citeseerx=10.1.1.483.1889|year=2007|s2cid=43610342}}</ref> A male that occupies a new territory appears to alter its yodel to be clearly distinguishable from the call of the previous territory owner.<ref>{{Cite journal|last1=Walcott|first1=Charles|last2=Mager|first2=John N.|last3=Piper|first3=Walter|date=2006|title=Changing territories, changing tunes: male loons, ''Gavia immer'', change their vocalizations when they change territories|url=https://www.fws.gov/uploadedFiles/Walcott2005.pdf|journal=Animal Behaviour|volume=71|issue=3|pages=673(11)|doi=10.1016/j.anbehav.2005.07.011|s2cid=43750841}}</ref>

A loon's wail is a long call consisting of up to three notes, and is often compared to a [[wolf]]'s [[Howling|howl]]. It uses this call to communicate its location to other loons. The call is given back and forth between breeding pairs or an adult and its chick, either to maintain contact or in an attempt to move closer together after being separated.<ref name="vtfishandwildlife" /> It is a loud ''aaoo'', ''weee-wea weee-wea weee-wea'', or ''ooo-aaah-éééé''.<ref name="hbw2"/>

The hoot is a short, soft call and is another form of contact call. It is a more intimate call than the wail and is used exclusively between small family groups or flocks.<ref name="Mennill2014" /> The common loon hoots to let other family or flock members know where it is. This call is often heard when the adult loon is summoning its chicks to feed.<ref name="vtfishandwildlife" />