Q January 
Zoo Dept. , 
Oxford . 
Dear Martin, 
Man y t hank s for 
Aerial Hostile Patterns, 
like to ask about. In your 
calls (of certain spp, ) seem 
sending us your summary on 
There are a few points we woiikl 
letter you say that all the 
to develoo from the distress call 
• 4 » 
hatched chick. Why distress ? 
of the late embryo and newly 
Is this different from the f odd begging: call ? 
The mention of Ri s s a on p.4- is presumably a misprint for 
xocxxx Sterna. 
Esther says that what you tell of the Plaintive Charge Call 
reminds her of the * wake'' of the"ki ttiwake" or of the moan. 
Whether these two ±h±xgx calls have a common origin she seems 
unable to say. It would be nice and simple to think so but 
apparently in the aggressive ki ttiwaking when a bird is really 
excited the second svl Tab le i sounds much less l ike the moan 
than it usually does. <*»<■< 
The business about special postures shown by the flying 
juvs. sounds most interesting and important. I have kept 
a look out for this Ip. the young terns after I saw in i 953 
that a young Roseatl^Ud the stretch a number of times when 
SJ 
% 
f 
ilk 
i^/fied that the young 
y some individuals more 
its parent landed near it. i am 
Arctics rarely do a stretch ; 
than others. It occurs in much the same situations so far as^ 
I could judge as the adults would use it. I could never 
distinguish any other "courtship" posture by the young, except 
of course the hunch. which in any case is difficult in ^ the terns 
to distinguish from the resting posture. Io\X mill doubtless 
tell us in your summary at what age you say these new postures 
in the flying juvs. It may well be that since I only watch my 
young terns for the few weeks after they can fly before they 
leave the island thayxxsxidXHSixaxsxxxxx I would not see. them 
if they occurred. 
I am not convinced from your description about the difference 
between the Swoop and Soar and the Swoop, Rise and Hover, ttiat 
is if you mean by using capitals, and I believe you do, tnat 
these two things are somehow differently ritualised. It 
would seem at first that they are merely different responses 
depending on whether the object threatened ls more or. less 
mobile. Or perhaps, from what you say on p.6, you think tne 
No from your motivation diagram it is clear that you think 
the' level of drives- is dif ferent in tile Soar and the Rise. 
same. 
3 !) * ^ 
