_ o _ 
but other calls appear apparently de novo . Do you think this 
is a real disagreement with your findings in the Franklin's 
and Ring-billed^ G-ul Is ? 
You remeoer the Ascension trip I told you about. 
I turned down tW ide* in its original form but have accepted 
instead the idea of going there for 3 mon 
(our winter), partly to give the other people* s<M3 ~oea 
of what kind of studies one can make in. tne field and partly 
todo something myself. You wrote that you intended^ to 
make a thorough study of the Noddies, the Fairy Tern and Ternle^q 
From what I know of your" methods" I presume that Jou confine 
yourself to displays and wont be making a v&vft study of 
the general breeding behaviour. Is this correct ? On 
the assumption that it is I think there will be plenty 
more which one can do with the terns there (Sooty, 2 Noddies, 
and .Fairy Teir$ . One idea I am keen to work on is a comparison 
of the two Noddies to see whether the apparent nest-site 
differences can be correlated with other differences in 
behaviour. I would also like to do some wofck on the 
incubation and parental behaviour with experiments on 
egg and young recognititon which I think can be done 
with mbxb a different viewpoint than before. Naturally 
I shall also look at the displays to see how they compare 
with the species I know, but I realise that you are probably 
able to go much farther with this ihan I can, on the basis 
of your wider comparative studies. X shall look forward 
for example to seeing the aerial dispiay,:fcBxsxK especially 
the High Flight, to see what happens there. - If there is one. 
Of the other people on the expedition one hopes to work on 
the general problem of the seasonal periodicity of the 
Sooties and the other will perhaps have a look at uyg 1 s . 
Neither is madly interested in behaviour in the narrow sense 
so I don't think they should conflict very much with your 
work but I should like it, all the same, if you were able 
to let us have a. scheme of the sort of things which you 
have covered. You might at the same time tell me^the 
sort of things which you might like to have more information 
about than, perhaps, you were able to get in the time. 
4b All snax my plans turn, of course, on when the oirds will 
breed. Oc^/Nov seems likely for the Sooties and the rest 
probably Nov. So I can t make up my mind too definitely 
in advance. If no bird breeds during my stay I shall have 
to train to land- crabs J 
Thanks for the information about tern systems tics. 
I wonder where Chlidonias fits in your scheme and do you 
include Phaetusa with S te rna ? or is the scheme deliberately 
Incomplete ? I have been puzzling about the question of 
forked tails for a time and it seems to me that they might 
well develop independjly in more or les s square- tailed 
birds which take to feeding by flying slowly , close to the 
speed of stalling (as Sterna does), over the water as it 
searches beneath itself for prey. Indeed one might expect 
