You list a number of calls of Franklin's gull. I wonder 
If you have worked out the homologies between the calls of the 
various gulls, and in particular how you have managed to fit in 
the kittiwake. Food begging, choking and the ( rare ) alarm 
call are clear enough but the kittiwake call, the moaa and the 
"go" call seam difficult at the moment but perhaps with your 
wider experience of the Larlds you can include these too. 
For example we don't really see why one should call the kittiwake 
the long call as Niko does, in every public pronouncement on gulls. 
But perhaps you can distil from the several species you have 
looked at some common characteristic of the long call and the 
other calls which would enable homologies to be established. 
One of the main catches about the kittiwake call as being the 
long call is the idea that the kittiwake call may lt3elf be 
Franklin’s gull makes one think of the mew call of the herring 
gull and the moan of the kittiwake. What about the blacd-headed? 
I wonder If you have tried establishing homologies 
between gulls and terxns, I see you relate the attack call and 
I don't know where I have this idea but if so it would seem to 
be like the soft call which I think is found in the terns. d3ut 
later summaries. 
I am filled with admiration for your motivation diagram 
explaining the aerial display. T wonder how you arrived at 
it. We find that as soon as we start, complications and contrad- 
ictions set in very quickly. Incidentally we found it easier 
to represent the motivations on a two dimensional diagram 
than with what Esther calls factory chimneys. The main advantage 
seems to be that one can then more easily express the variation 
in motivations which gives rises to a posture. Thus any pair 
of factory chimneys can be represented by a point, just like 
the coordinates of a graph. But if you want to express that tae 
same posture can occur, for example at variable amounts of 
attack drive while the e scape drive Is constant, then instead 
of having to make two or three pairs of chimneys, tnis is represented 
by a line on the diagram. Or if both attack and escpae can 
vary over a certain range independently and yet the posture 
still, occurs , this Is expressed in the diagram by an area. 
There seems to be another advantage of the method. e oo ar . 
a combination of the choking call and the moan. 
The combination has certainly be ritualised, whatever that 
means, but is not completely implausible though di^icult to 
prove it seems. Your mention o^ the plaintive charge call of 
the gakkering, or what I call the chatter, 
have a growly call at nest relief typical 
Don't the gulls 
of the broody bird ? 
perhaps you have set out some of these things in one of your 
coordinates of a pomtx ' see a 
you observe in your counts of 
what precedes attack, etc. 
The likelihood of a posture 
leading to attack is shown 
by the angle & while the 
of a points: f see diagram) express the two tnings wglcn 
... # 
X % 
Intensity" is shown by r. 
't 
% ■ 
-£ . 
