a H 
6^ l f-*- c*for***,«_ hWv 
During the recent summer i have hiu a chance to look at ana 
compere 4 spp. oi terns ;s there were nesting on the Inner Ptrne 
Com oh, Roseate ana Sandwich t s well as the Arctics. Th,, three other 
sp o ' have nestea in other years tame* but in less numbers and 1 haven't 
had much chnce to look tt them. There are some interesting aiwerences 
vhich 1 though you might like to hear about. Xfeatxu&juuuLy ^ As 1 
think 1 m? y have told you before the Arctic ana Com on terns seem to 
have an almost identical behaviour. 1 c. o ncluue this from my ov.n ooe 
ana those of the hutch fellow, Schenk, who has been looking &t the 
Common tern. The Sandwich however is different from them in a g react 
any ways, both morphological and oehavioural: 
. The colonies are far denser and th- young are lea away loom the rest 
soon after hatching. 
i, Pr- sumabxy adapted to this last uii ierence much ue lmviour It eking 
to conceal the neot which , s pres ent in Arctic <1 Common. The brooding 
adults do not fly away from the n st to aeisec&te but do so a few 
inches from the nest and tile young a o not walk away to ueTi ecate : fast** 
the e shells are not carrie. away the young ha tch. Ntnutik 
Cs ilJ-JP’ t r.ViAf in AW 4 , -4 i- s 
5. 
7 . 
The "normal" aggressive response oi 
to ; not her is the t: eic. ering 
This ffiigio of course be because the o*e*s a: 
1 have indications that it is not merely th 1 **. ^ * v UA1)a * 
you once oeiore i know wha t the gekkering is homologous 
itos in th Arctic and Com; on out it io ra rely to so seen unless the 
intruder comes close to a bird who is unwilling to leave its nest 
to attack, say a brooder. 1 have not been able to establish 
any homologues of the Arctic’s normal aggressive behaviour in the 
Sandwich though some elements may perhaps oe recognisable. 
incidents ly in this gekkering the crest is strongly rt.isea, a s you 
know, while this structur e is almost absent in Arctic ana common. 
One oi the most conspicuous calls oi t h~ mrr hi : ? the Pish call 
( though £ fish is not always Carrie a when it is given) , se-ms to play 
an important part in pair formation ana m inta inin e , contact between 
the two mates enc. probably also between parent and chick, 
coos not occur in fight* &uu there is no reason to think it 
aggressively motivated. Arctic ana Common se-iu to have a 
which is charca terist icaily a ssocia tea with ' t fish out this 
occurs corns only in fights, ana is clearly ag c re~sive. 
The food begging is somewhat • aii^erent ana more gull -like, in 
Arctic ana Com aon the neck is withdrawn in food-bo ging, into the 
hunch posture. The calls are then utterea from thi* position, the 
bill wide open without head tossing or bobuing, ana the calls, even 
at low intensities consisting oi "bursts’* of incividuel syllables. 
In the Sandwich there is the seme withdrawal of the neck nto the 
riuiiCh posture but JckK each ca-11 is more single and is assoc it ted 
with & clear head tossing movement. only at high intensities ao 
the single calls oecome run together and evenatxthen they are more 
irregular tht'r. in t e other two sop. 
Of the morphological diinerenceo you probeoly kno more than 
i'he most striking (a part from the crest) are the plumages of 
^oun^ana the first juvenile plumage. There arc also such features 
This cell 
is 
call 
call also 
I ao. 
downy 
