4^ HML 
A bird usually reacts tr^ the pre:^encc o£ cthc£ 'oirtSs by shcs^dt^ t 
ccotradictory ami ^oie or le*5 ^ inconpnti" ^ ' ^eo<^^eficieB. It is of^f^ » 'rtly 
hostile Md partly ' f ri«iidly'\ api>arentl> In the otb , and also 
nttack thfflt an^yor escape froia th« at t!. , rhc r»olatxr 1i 
coofllctlns ^ '^ 'oiis ia a particularly ^-^.^^-. It problem in — 4^ -4. - 
spades^ wlAcu lm« had i ^^a« nethoo^ of both incieasiflg the general social ox 
f loc ^ awltsi^es '^w^ rorttroHii^ the hostile respoflSM v* are provofead hy 
any close aasociatici 01 .^a. •:;.ciit i uais, (it sceas to be very difficult, i^e. 
very disadvr joous, to dit th koatility altogether) • Moat gregarious 
spec^ ve evcrived Bpecit^':^ ctaptivc hdiavior pattcras in order to attain both 
obJectlTea^ 
The pattecBS \4v.lch hcl^ to pronote flockii« are wttslly (torioua iukl roi -Uv^^y 
slm>le^ ^IflBKMit all the highly gregarious sp^clee have developed special socir l 
calls p cooapicuous vdm aa4/or tail raovojfcsnti., and (> .y frervtently Increased 
general uidbility or ' restlsmaaeaa'*, all of Whicli seen to be demi^am* io iBcrea.sc 
the attractiveness of a i^ocial ^oup and naintain ee*esio« within it* Sone 
gr^atious upccies have developed suc^^ - - cters .xwi^. c.v ijreatly altcrir^ the 
••hierarchy of in' tincta' f but others havi •> eroXved a special , and more or less 
inA»rv^rmr»en general sociar' drive or i4tich is sk^ found in acre soli / 
The codtrol oC hostile reape^ses would seem t ^ a Mre c 
in sKKje resp^s, and h - acldeMd by a great variety of laertherts^ Sone 
^species have evolved sp<^al displays (r5 " li:^ ' x.x.-j. x^nals) \diich ^^y ii&ed 
by one bird of a g p to t^Amcq the str oi tiie in :vxl attack aoiVor e 
drives of other aesfrers of the ..^ , oth^ spcci^^s have developed dir; 
vdtic/ ' to div^wrt the overt es^re- ' ho^ .j.lity ^he group into 
relatively handess dVMBels. The ov ission <rf h08>tiixi;y laxy even be ny vu c 
>fithout the intervention of special . , ^ directly reduciaj the resp use to 
certain particr^ • ^ of hostile sti^^Ji {uitU-«wil wealDBni'^ ^ne internal hostile 
ch s ingeSMuraii, ieae species nay u iifferent net hods xn ijiifferent circun- 
stances} aad these vari^itiiws would also seea to be adaptive^ in : owe cases at lea^i 
as they can be correlated with piMf^^wular factors of eacteraal envir omaent » 
