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and the pair are more relaxed together. Even after the pair has formed^[[,]] the definitive nest [[strikethrough]] site [[/strikethrough]] ^[[place]] has not been chosen, as the pairs visit different [[strikethrough]] ledges [[/strikethrough]] ^[[sites]] together in different parts of the cliff ^[[*]]. [[strikethrough]] This [[/strikethrough]] Th^[[e]] ^[[decision]] is evidently deferred until closer egg-laying, in which period also courtship feeding and copulation presumably become commoner. 

This general pattern is not very different from the pair formation of other gulls and terns. One point may be mentioned: the selection of the actual nest site only after the pair has formed. This is what happens in the ground-nesting gulls and terns, but the Kittiwake pairs on its nest site, a difference thought to be due to the relative shortage of nest sites on cliffs. One must suppose that such sites are not in such short supply for the Black Noddy or else that"house-hunting" pairs can readily evict unmated males [[strikethrough]],[[/strikethrough]] when the time comes. 

[[strikethrough]] 3. It is well known that the pair-formation and "greeting" displays of many birds involve the same posture and calls as occur in fighting behaviour. In some cases however [[strikethrough]] [[?]] [[/strikethrough]] there are differences in the orientation of the displays. Thus the friendly "triumph ceremony"  between a pair of victorious Greylag Geeser [[underlined]] Anser anser [[/underlined]] is like a hostile [[strikethrough]] [[?]] [[/strikethrough]] demonstartion except that the mates display past, instead of at one another(Lorenz). The Black Noddy's g ape is another host ile display which,used between the mates, tends not to be orientated at the partner as it is at a rival. The oblique and forward displays of the Black-headed Gull [[underlined]] Larus ridibundus [[/underlined]] are more regular elements of the greeting than the Noddy's gape and the pair commonly perform them side by side. [[/strikethrough]] 

^[[*a point confirmed by Macgillivray who observed the species nesting in trees.]]   
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