( 
of tun AroUc Tarn. 
A grent many words hf v& been written about t^me shd It 
is « oeniH«i«bIt effort merely to roti tbia hodjr of literature# 
In such ns t tors a® the longevity and tendency to return to a 
turner brooding place a great deal is known thanks to the work 
of the Austins on the Common Toms in Capo Cod, Massachusetts* 
Nevertheless most of the studios of behaviour nave boon dossri >tive 
and it was ho nod that a. start sight bo mads on an analysis of 
tho causation of the behaviour In sane sort of way as had boon 
done with tho gulls in the development of Dr Tinbergen’s 
programme of studios. For this reason I spent a fragment of 
»95? and the summers of i 953 and t >34 in watching the ro reductive 
behaviour of tho Arctic Tern. I made little systematic attempt 
to study tho fishing apart from a purely doscrl tivo one# The 
way in wh i ch tho terns find fish ia certainly interesting and 
it is very impressive how quickly a group of diving birds 
attracts other®. One can also matt# out certain regularities 
in the plao o where they choose to fi h. Near th© ifl’nd they 
select the so n© around the patches of u dwelling water where t s 
tides rim fast over sows irregularity# I collected earn lea of 
a few preys and over a period of two weeks when the young were 
being fed I counted the proportion of sand eels and other re/s 
er-rrls by brents# This hosed tha^ U~t^ , ro ortion of ssnd 
oels, by far the component rey, varfefjpe^we , n r 'A i • nd , >uch 
ft difference must have refeleoted a real difference in tic 
prey caught# The newt commonest prey at thi® tl e of ye< r was 
wh- t woo •orobftbly one of the herring foal ly , nn toh n 
which I wan able to examine was a young Herring, It t pears 
possible to me that not only is the forced tali of tern® a 
snecia 11 action for fishing but that hare might also be < reason 
why the forkinsss of the toil varies so much from species to 
species# If one comperes the fishing of sjiio and Arctic 
tern® It seems that the larger birds get their prey more frequently 
by diving. The Arctics usually feed by werely e <oo oing to tie 
'water surface a ilokit me thing off, often without immersing 
themselves. Perhsn# {and a® yet I can my no more) it is the 
half •folded wings which exercise the main control during the 
s tee o dive while in the shallow swoop the tail plays a gras ter 
art# One could pert' inly find out whether it is true that 
the Sandwich really dive* more than the Arctics and one might 
even find differences bet ten Arctic and Roseate# The Roseate® 
© round the Inner Fo me were rarely seen fishing by me# Their 
usual method of getting food seem® to be to chase other terns 
end snatch the fish from them# They certainly have ama singly 
quick cower® of turning which would be facilitated by their 
long tails. Although they are able to fish like the other terns 
It is orobrbly no coincidence that with such a swift flight and 
powers of turning they are adept at robbing fish. Arctic and 
Common also try to but rarely succeed# 
