f 
Zoo Dept. 
Oxford. 
Dear Martin, 
Thanks for your letter. It was most tantalising 
to hear about Laros terna ; I am only sorry that you didn’t 
describe any of its postures. I hope you wil.l be able to 
let me know something about the form of the movements at some 
not too distant date. It must be an astonishing creature, and 
it made a great impression on me from the first time I saw it in 
Murphy. . ■ - 
In answer to your questions I think you will find that some 
points have been answered in the report on the Gull 3c Tern 
conference which I sent to you via Frank some time ago. If 
this hasn’ t yet got to you let me know and I will stir up Frank, 
though as you probably know he Is having great worries at the 
moment as Brenda has severe cancer. 
The Dutch tern people don’t seem so Interested in the 
comparative approach to the terns and concentrate more on 
counting postures 3nd' things like that. However the comparative 
side interests me quite a lot, though from the poLot of view of 
radiation fcather than taxonomy - if you see what I mean. 
I come more and more to the view that it is extremely difficult 
to compare on the strength of the observations of other people 
especially If those people haven't seen more than one species. 
Consequently I • m happiest in comparing the four species which 
I have seen* Arctic, Common Roseate and Sandwich. Bergman's 
film eked out by his pa*p<lr* fend vice versa) are also useful 
because the Caspian is so similar in many way to the Sandwich. 
On the other hand the Black Tern is sufficiently different from 
any of the other species for me to find a comparison of the 
calls, for example, extremely difficult even after having seen 
a little of the beast. I dare say if I saw it after having 
watched the other species I should understand it better than 
I did when I was just beginning to know my own species. 
All this comes as a preface to an attempt to tell you 
something about the calls of the Arctic and other species of terns 
What I shall do is this. First I will tell you about the Arctic's 
calls and then give a table purporting set out the homologues 
of the different calls so far as they are clear ( and in some 
cases perhaps wherp they are not). At thejend of the table I 
have tried to give^an idea of the chare ter of the cal 1 common to 
its forms in all the species, which should assist in determining 
the homolgues in other species. 
