the birds travelled, a© they flew in a purposeful way straight 
to the other Island. the distance from ths n^rth-enet corner 
of the Fame to the main roost Is about I nils II f> yards, runs 
flights in alt were timed on two different ds/s and the lias 
t trtn to cover the distance varied between l 'JO and in seconds. 
The js.vsrs.gs speed for tbs nins flights was n. p. h* 'on both 
evenings there was only ft very light southerly wind so t oat 
the actual air-speed was probably about 30 m.p.h. 
As ths season advanced the time the last bird left a 
particular grotto of nests to# ©&®s later and later in rs .. t i o n 
to sunset as sell as to actual time. By th fourth week in 
rch - hi r ! w ' L ■■■■ :; ' ■■■ t ■ tv r t liv* ■ ■ ' 1 " h - n " *** 
individuals were those whose bresdong cycle a wsrs moat advance 3, 
But there wsrs still sous nights when no birds roosted at ths 
c my. The norni g attsndanes was mu aors regular than ths 
evening and sobs pair# could hardly be said to e evening 
visits at all. 
From ths beginning of the season a few birds behaved as 
if they were already paired and nearly always stood together on 
a particular ledge. It w»s probably significant th&t these 
veil* pal rad birds were on the ’’best'* ledges. However -most of the 
birds did not give the i&creaslon of being de inltely paired to 
* particular individual although fros the earliest they might 
show some slight prefers nee. the sales who were not ;airsd 
would snend Ion# 1 ; inactive periods on a chosen l*uge t *hju:^ 
Were lnterupted for bouts of advertising display towards fern; le 
shags who came near. The male attracts fern*. lee with this 
display. Some of the® he oec'ts away, others he accepts for 
a tine but then peeks them away. Gradually he establishes 
a preferenc# for one and will peck away all the others who 
come to him. Another change also takes place* In the first days 
as soon as a female left the male he started one© again to 
advertsle* later this becomes lea* and lest ely and as a 
result he is visited less and less by strange females. A 
discussion of the details of the motivation function and 
origin of the male’s advertising postures will be deferred till 
is ter. c ■ ' - *i ' - : , n ’ ’ / ! 1 9 -•"• Sij5 S, i i fei 
Whenever -the rightful female returns to her mate they 
show a ’’greeting” display which develops out of the mors or less 
hostile manner with which the un -a ted male gecslved a female. 
The vest Important feature of this greeting Is toe Appeasing 
Howard Oaoe display which both birds now give, not merely tr.e 
• . . ~ f Mu 4 Mri *s» nr\ T /A Si £& * 'i ; t '.d 
This 1® important as showing 
longer so hostile to the approach 
at the ledge and the male 
greeting. This- regular greeting * 
at ths r. turn if the sat. to tie neat o; usea on« to f org«t that 
ths pair say »«U bo sltshtly ho.tlto to <»• rl; d „ 
to howsver shown by »uoh observations .•» *b. foUo.ln®. on. ley 
ttt.rs «08 8 .iron* wind blowing on to th. ollf. *h.r. i w»» 
v rrlv e as occurred earlier 
that the bird on the ledge is no 
of its mate. When the female is 
alights there, there is the same 
9 
