Editing Tern (section)

=== Voice ===
{{listen|filename=Sterna-hirundo-002.ogg|title=Common tern (80 s)|description=}}
Terns have a wide repertoire of vocalisations. For example, the [[common tern]] has a distinctive [[alarm signal|alarm]], ''kee-yah'', also used as a warning to intruders, and a shorter ''kyar'', given as an individual takes flight in response to a more serious threat; this quietens the usually noisy colony while its residents assess the danger. Other calls include a down-slurred ''keeur'' given when an adult is approaching the nest with a fish, and a ''kip'' uttered during social contact.<ref name=hume68>Hume (1993) pp. 68–75.</ref> Parents and chicks can locate one another by call,<ref name= burton>Burton (1985) p. 123.</ref> and [[sibling]]s also recognise each other's vocalisations from about the twelfth day after hatching, which helps to keep the brood together.<ref name= sibling>{{cite journal | last= Burger | first= Joanna | author2=Gochfeld, Michael| author3=Boarman, William I | year=1988 | title= Experimental evidence for sibling recognition in Common Terns (''Sterna hirundo'') | journal= Auk | volume= 105 | issue = 1 | pages= 142–148 | jstor=4087337 | doi= 10.1093/auk/105.1.142 }}</ref><ref name=Stevenson>{{cite journal |last=Stevenson |first=J G |author2=Hutchison, R E |author3=Hutchison, J B |author4=Bertram B C R |author5= Thorpe, W H  |year=1970 |title=Individual recognition by auditory cues in the Common Tern (''Sterna hirundo'') |journal=Nature |volume=226 |issue=5245 |pages=562–563 |doi=10.1038/226562a0 |pmid=16057385|bibcode=1970Natur.226..562S |s2cid=4181980 }}</ref>

Vocal differences reinforce species separation between closely related birds such as the least and [[little tern]]s,<ref name= Massey>{{cite journal |last= Massey |first= Barbara W |year=1976 |title= Vocal Differences between American Least Terns and the European Little Tern | journal= The Auk | volume= 93| pages=760–773 |jstor=4085004 |issue=4}}</ref> and can help humans distinguish similar species, such as common and [[arctic tern]]s, since flight calls are unique to each species.<ref name= const>Constantine (2006) pp. 73–77.</ref><ref name=burger/>