4 
of the behaviour of unma ted males seeking a female. Again and 
again hie on®- time sate, Dot, would fly to him, beg the fish 
and take It to feed her own young. ■ This does n:>t constitute 
any act of reeogni tlon between the two birds though the male 
©ay have recognised the female. He behaved toward# her as he 
would to any female ho was trying to mir with. On the other 
hand her treatment of hi© was quite unlike that of a female 
towards her mate Imt was the way a feme 1© feeding chicks might 
reset to any bird with a fish. The fact that the terns tend 
to return to about the same area of the colony "her© they bred 
or tried to bread the previous year will of course t nd to bring 
old pairs together age in and indeed I had several pairs, including 
filliam and ilfery, who bred together in successive seasons. It 
is difficult to decide whether the re Is any preference at all 
for the ©ate of the previous year {as was found in the kittivake) 
but it would see® likely because the nest site of the previous 
year tarn be 1© I very accurately on the sand. irlng 
the winter the height of the beach shifts and changes he cur 
In the landmarks on the sand* The fact that pairs rejoin one 
another in/s bite of this? suggests that they rust retain some 
memory of the individual appearance of the old mate or of its 
call. Tills is not surprising a® they certs inly learnt the 
appearance and voice of the ©at© duri-.g the season. 
.it 
The behaviour of males before they are paired consists 
of resorting again and again to a ©sell are© of ground, perhaps 
only s few feet in disaster which they use at: their head-quarters 
in their efforts to attract females. Although the birds my 
return regularly to quite a limited area they do not spend ■ ucir 
time there continuously. For e:-:asq i© Dick who fa iled throughout 
19*54 to got a female nevertheless uerferaed his advertisement 
displays’ {to be described la ter) only In a small part of the 
area where I ■& de my day to day watched* I could not exclude 
of con “S' that he did net display anywhere else in the colony 
or outside It, but the fact that he did not die play in other 
arts f the study ret :eats that his sphere of influenece 
say have been quit# small. Me displayed there from 15 May 
until mid -August though often I saw no sign of him for sever: 1 
days. Some birds were clearly not restricted to n single diy lay 
area throughout tho assson end » few even resort d to two areas 
alternately though both were quite small, t- few yards in diameter. 
Thus I believe that the males who are seeking to attract females 
display in particular spot© widen they C:»se in or around the 
nesting 1 ai?*» Cf the ■ colony. But they a od no ©ore tb i a email 
Percentage of their time actually in these areas. This was one 
of the difficulties in watching the behaviour of uni: sired birds 
to discover how they received females, One ©ight watch an area 
whore one morning 1 s observations had shown fc?:u t & certain male 
spent his time. The next day ho might be completely absent 
during a watch of 5 or & hours end the following day he might 
appear again for only half an hour or so. On the whole 
it seems that the mornings are the most likely time for birds 
to visit their territories but even then there see© to be gaps 
