A*. — 
6 . 
7 . 
8 . 
9. 
10 . 
1 1 . 
*?he 
the Chhtter, 
next call }i Is given by birds who swoop down to attack a 
predaa tor in ‘'the colony! It is the familiar " tiki tiki tik. .. " 
This call is also uttered on the ground e.g. by brooding birds 
when others approach near, or when a rab'it or some other species 
coraei close to" the brooder. On the ground the bird stretches 
towards the intruder as far as it can without rising. I 
haven’t been able to detect any feather erection. k I have 
little doubdt that this has a common origin with the gekkering 
of Roseate, Sandwich and Caspian. 
At the bottom of the swxoop at a predator the Arctic tern ca{Ls 
a loud "kyow", or something like that. This seems to be a different 
call from the cha tter and can be heard on other occasions too. 
When two terns are fighting in the air and ^c end in an 
upward flutter the same call can often be MMl. And it may 
be heard, with or without the chatter, as a tern attacks and. other . 
The call seems to come at the moment of closest contact with 
an opponent. 
It is sometimes possible to change the "kyow" last mentioned 
into another call. If a tern is swooping at you with the 
"tiki tik" and at the last moment you jump upwards at him, he 
doesn’t call "kyow" but instead a musical "kliu". This kliu 
is also heard under natural conditions in circumstance suggesting 
it is rather leas aggressive and more frightened than that 
"kyow". There are two sitae conditions when it is particularly 
common: during the ascent of the High Flight, by the following 
or pursuing bird, and as a response by brooders to a gull approaching 
the colony when the birds who call leave their nests and attack 
the gull with the" tiki tik kyow" form of attack. 'The form of 
the musical kliu does not seem to resemble the loud "kyow" but 
I think they are rether similar and hope one day to make a spectro- 
graphic analysts. In adults 
Food begging call. shrill "kee-kee-kee " at a 
of about 6 parr second. In chicks the call has about 
maximum frequency but each syllable sounds more lime 
Male conulation call. Before mounting it seems like 
ky2 and after mounting and during copulation a my f fled ky-3. 
When the adults are handled for ringing the birds occasionally 
uttered a very shrill, high-pitched "keer". This call is 
distinguishable from any of the others though perhaps grades 
into the "keyairpr". I have also heard £t from birr® who 
were involved in fights and were trying to pull themselves away 
from the grip of another. When they young ar’e handled they 
give a loud "shri" but this doesn’t sound like the"keer" at 
all. Perhaos it develops into it; perhaps it doesn’t. 
In the chicks this shri seems to grade into the syllable of 
which the fo rs d begging is compoased. 
Here then, for wh4t it is worth, is my list of the calls 
of the Arctic tern. The Common terns appears to have an 
almost identical repertoire though the whole tone is gather 
different. The most different calls from the Arctic s are 
frequency 
the same 
"shi" . 
a raufif led 
the alarm call when you walk in the colony, which is "keyalrrrrrr" 
with the accent on the second syllable which is more drawn out 
than in the Arctic, and in the calls ky2 and ky3 whiclj 
