Schenk talked about the aeri?l display of the Common Tern. His 
account agrees very much with mine with two exceptions. My account 
you have read ; lready in that report lor the lateral History Society 
people who administer the Parnes. The difference in our two stories 
may well bereletod to thefect that his m? in observations were made 
before the hires alighted at the colony at thebeg inning oi the 
bre.:Ciin season while mine were made after this time. His facts 
may therefore represent an earlier stage than mine in the s A 4 $y f cle as 
a whole though not, i believe, in the secuence of an individual 
pair formation. I described as different displays what i called 
h flight and what I called the Advertisement fligh . According 
to Schenk the Advt / ili e i is the inningof the H.flig ,ndthey are 
not separated, asyl thought typically, oy the. bir us landing together 
on the ground. / / The other difference bet een oUr two accounts is 
the t he thinks that ex her male or iesale way the pursuer in the 
high flight ascent^ and that there is no change over in there les at 
the begin ing of the glide of the high flight. 
filth regard to the motivation of the displays we are no it , ther 
forward than before. Certain parts lo k rather aggressive out never, 
or hardly ever go into attack. If a third bira joins in the display 
and overt a ression r; ises i s ugly herd the di hole form oi the display 
alters. Lastly, i erial fights between birds hardily ever go over into 
genuine aerial disolay. in spite of all these difl iculties I 
belaieve there might once upon a rime have been an tg restive origin 
to this behaviour ano the gulls' aerial aikax ceremonials makes it 
led II the more likely. 
Concerning the i unction oi the behaviour Schenk and i 
are 
more or less in agreement that it seems to test the bond between the 
pair. 
van den Assam was unfortunately unable to be present as he is doing 
his military service. Ho ever there was present a girl called Angels 
LSI who had jscxxx made a study of head shaking in the Sandwich terns 
anu ws very familiar with the sp0. , .Iso a man calleu droot 
who had made the film of the Sandwich terns which w as shown ana 
himself knew something about this species. 
3ol gave a talk abut the 8. tern end the following information 
comes from her speech together with replies to questions 1 a skea her 
,at the time and after seeing the film. Home of the things i have 
Mentioned before in con. ection with my own observation on this sp.; in 
comparison with the Arete, Common anc Rosea to on thw-Haras s. 
The gekkering you know. It seems often be followed oy libation 
of the ground in i ont of the bird in a way which shows si f the 
crest *"° ori S in to this fixating movement s sug cited. I have 
seen*' in the Arctic tern what seems to be a very similar thing in ^xxsJt 
similar situations. ru :iely after three tening, but 1 too have no su e&ted 
origin. It may perhaps be the t this downward movsm ent is incoporated 
into the bowing or nodding display of the Arctic tern whic h you have 
sewn yourself in hostile situations. 
i’ 
