n 
another in drttf to &<?t a flit, 9F to rmmt or to be aounted; It 
r^y b« that the reason which aRueed it V> op roach cl os# - > th# 
other has suddenly disappeared as happen® vhcn a ®aie brings 
© fish to hi*i u to aid at once doc a a atr**teh nftor she 1'uo taken 
it froK bio* But in thee* situations where tho darn posture 
oo aura ear la not am by anythin whia drawa 
the torn ©lost to the frightening object, "nly when there la 
© conflict of f et v -?l th sense thin*, alee s '-*n- V •? bird stretch* 
i 
*fhf ro la one posture no re whoa# ©otiv&ti >n 1 wtnt to 
discuss* Thl© l© the bant, wh3 •‘i reacts vr- tv the 
*1 ifthtln?. of Us f ettr. la an; does not occur in fl-hte* ^ However 
so tines that t : nit reacts to ■ tfcor .bird wit;; 
the bant and then this m las ini the crouch if the ©that* doaan't 
react suitably and nay tins y end in an attach. '"ha fact that 
the emush and heat can grad# into >n* another in this situation 
and that they hare ©ertein i©;>orUnt elements la c vamon surras ted 
to ■ - b Aon ;;v ■.■■:, >■ 'iff francos between 
on : i hly att#$v -ire* Ti f' . f the two 
towards* the srovofcla« bird® le very different. Thu crouching 
bird fees a precisely toward© the other and di? '‘lays hit black cap 
n thla way* bant bird* however, ta>ea • i bar of re caution* 
not to show his black cap to the f crania • Firstly he tend© to 
i his In such a way that ah# la >r e >raar- . to ona 
aid# rath than direc y in front af bin* Be. idly he tends 
to bond hi© head and neck sideways away frota hot and thirdly n© 
- / rotates the heed about its axis so toot th •'••db 
ear is turned further fra© bar. This last affact 1 call filtili 
and la also very conspicuous in birds in the atratCh. Thus 
cosriorin.k thaae two postures we aae that in the one which is 
» e tatatio a wala raa .» cap toward* an 
opponent while In the #ra « ting he reran te her saeini? it. 
F •••' ■ aba • ’ ‘ • i c ifiroed what will sire- . have be a guataad 
- , a ware fright#* >ther tarr « ra«ti®ea 
a fanf.te taored around a- ©ala whan he was f. '■ engrossed in his 
dlsolay th"t l«.e did not change his position. On c© tchl nr. eip.n t 
of hie cap ah# at once moved farther away fro® hi® but was 
reassured whan ha once war# tilted it away fron her. If there 
were a predisposition in a ora© ancestor of the Arctic torn to 
•rforw a- catila lotlea lit# the crouch towards faaaits who 
visitad htw during pair ns tion kind thei art w sufficient 
reseona for this view) ona Bight expect tha t too sc terns would 
ir ■•''"• ily '■•ho lc©o'! o el. various ways of avoiding frio toning 
their visitors, ‘ I baliavc that it is such a *■ id 1 fixation of the 
crouch which has brought it into the for® of the bent today* 
Why the raodifl cations should have bran or Just the v lnd they 
are le another and a were difficult Question. 
So for X have SYift ©lasted no thing about the motivation of 
the reriel displeye. There is very littlv doubt that the firm, 
and therefor- .••raau®e jr the activ&u^u* f tha atratali ana bant 
rales in the aerial pass is- aimil.tr to whan they occur on the 
around. A art fro® this I have ••©* little convincing evidence 
